Orthopaedic fusion planning systems and methods of repair

ABSTRACT

This disclosure relates to surgical planning systems, instrumentation and methods for repairing bone defects. The planning systems and instrumentation disclosed herein may be utilized to establish trajectories of surgical devices and may be utilized to establish resection surfaces for fusion of adjacent bone surfaces.

CROSS-REFERENCE TO RELATED APPLICATION

The present disclosure is a divisional of U.S. patent application Ser.No. 17/482,103, filed Sep. 22, 2021, which is incorporated by referencein its entirety.

BACKGROUND

This disclosure relates to surgical devices and methods for repairingbone defects along articular surfaces of a joint.

Many bones of the human musculoskeletal system include articularsurfaces. The articular surfaces articulate relative to other bones tofacilitate different types and degrees of joint movement. The articularsurfaces can erode (e.g., experience bone loss) over time due torepeated use or wear or can fracture as a result of a traumatic impact.These types of bone defects can cause joint instability and pain.

Bone deficiencies may occur along the articular surfaces of ankle bones.Some techniques utilize a bone plate to fix the ankle bones to eachother.

SUMMARY

This disclosure relates to planning systems and methods of performing asurgical procedure. The planning systems may be utilized for planningorthopaedic procedures to restore functionality to a joint, includingdetermining contact areas between resection surfaces and establishingtrajectories of surgical devices.

An assembly for preparation of a surgical site according to animplementation of the present disclosure includes, inter alia, atrajectory guide including a guide body and at least one arm membercoupled to the guide body. The guide body may include a guide passageextending along a passage axis. The at least one arm member may bemoveable relative to the guide body to set a trajectory of a first guidepin insertable through the guide passage relative to bone. A secondaryguide may include a main body having at least one aperture. The at leastone aperture may be dimensioned to at least partially receive a secondguide pin along an aperture axis. The secondary guide may be coupled tothe guide body such that the aperture axis may be offset from thepassage axis.

A system for planning an orthopaedic procedure according to animplementation of the present disclosure includes, inter alia, acomputing device including a processor coupled to a memory. Theprocessor may be configured to execute a planning environment includinga display module, a spatial module and a comparison module. The memorymay be configured to store a plurality of bone models including a firstbone model and a second bone model. The display module may be configuredto display the first bone model and the second bone model in a graphicaluser interface. The spatial module may be configured to establish afirst resection surface of the first bone model according to a firstreference plane. The spatial module may be configured to establish asecond resection surface of the second bone model along a secondreference plane. The spatial module may be configured to position thefirst resection surface in contact with the second resection surfacealong a contact region. The comparison module may be configured todetermine a contact area ratio. The contact area ratio may be defined asa first area of the first resection surface along the contact regiondivided by a second area of the second resection surface. The comparisonmodule may be configured to generate a first indicator in response tothe contact area ratio meeting a first predefined threshold.

A method of performing an orthopaedic procedure according to animplementation of the present disclosure includes, inter alia, selectinga first bone model and a second bone model from a plurality of bonemodels. The method may include displaying the first and second bonemodels in a graphical user interface such that a first articular surfaceof the first bone model opposes a second articular surface of the secondbone model. The method may include setting a first reference plane inthe graphical user interface to establish a first resection surface ofthe first bone model. The method may include setting a second referenceplane in the graphical user interface to establish a second resectionsurface of the second bone model. The method may include generating afirst iteration of the first and second bone models that may excluderespective volumes of the first and second bone models between the firstand second reference planes and the first and second articular surfacesof the first and second bone models. The method may include positioningthe first resection surface in contact with the second resection surfaceto establish a contact region. The method may include displaying thefirst iteration of the first and second bone models along the contactregion in the graphical user interface. The method may includedetermining a contact area ratio. The contact area ratio may be definedas a first area of the first resection surface along the contact regiondivided by a second area of the second resection surface. The method mayinclude displaying at least one indicator in the graphical userinterface associated with the contact area ratio in response to meetingone or more predetermined criteria.

A method of performing an orthopaedic procedure according to animplementation of the present disclosure includes, inter alia,configuring a trajectory guide. The trajectory guide may include a guidebody and at least one arm member coupled to the guide body. The guidebody may include a guide passage extending along a passage axis. Themethod may include moving the at least one arm member from a firstposition to a second position relative to the guide body to establish afirst trajectory along the passage axis. The method may includeconfiguring a secondary guide. The secondary guide may include a mainbody having at least one aperture extending along an aperture axis. Themethod may include coupling the secondary guide to the guide body toestablish a second trajectory along the aperture axis. The aperture axismay be offset from the passage axis. The method may include moving thetrajectory guide into abutment with bone. The method may includepositioning a first guide pin through the guide passage and then intothe bone according to the first trajectory. The method may includepositioning a second guide pin through the at least one aperture andthen into the bone according to the second trajectory.

The present disclosure may include any one or more of the individualfeatures disclosed above and/or below alone or in any combinationthereof.

The various features and advantages of this disclosure will becomeapparent to those skilled in the art from the following detaileddescription. The drawings that accompany the detailed description can bebriefly described as follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exemplary planning system.

FIG. 2 illustrates another exemplary planning system including a userinterface.

FIG. 3 illustrates the user interface of FIG. 2 including displaywindows depicting adjacent bone models.

FIG. 4 illustrates the user interface of FIG. 2 including displaywindows depicting resection planes and a contact region between bonemodels.

FIG. 5 illustrates the user interface of FIG. 2 including displaywindows depicting resection surfaces, a contact region between bonemodels and exemplary indicators.

FIG. 6 illustrates the user interface of FIG. 2 including displaywindows depicting a contact region between bone models and exemplaryindicators.

FIG. 7 illustrates a visual contrast applied to resection surfaces alonga contact region between bone models.

FIG. 8 illustrates the user interface of FIG. 2 including displaywindows depicting resection surfaces, a contact region between bonemodels and exemplary indicators associated with a change in relativeposition between the bone models.

FIG. 9 illustrates the user interface of FIG. 2 including a displaywindow depicting resection surfaces and exemplary indicators associatedwith localized support regions.

FIG. 10 illustrates the display window of FIG. 9 depicting the resectionsurfaces and exemplary indicators associated with a change in relativeposition between the bone models.

FIG. 11 illustrates exemplary parameters associated with a bone model.

FIG. 12 illustrates the user interface of FIG. 2 including displaywindows depicting an implant model positioned relative to adjacent bonemodels and visual indicators.

FIG. 13 illustrates the user interface of FIG. 2 including displaywindows depicting an implant model positioned relative to adjacent bonemodels and visual indicators.

FIG. 14 illustrates exemplary trajectories for adjacent bone models.

FIG. 15 illustrates exemplary trajectories for one of the bone models ofFIG. 14 .

FIG. 16 illustrates exemplary trajectories for another one of the bonemodels of FIG. 14 .

FIG. 17 illustrates a perspective view of an exemplary trajectoryassembly.

FIG. 18 illustrates a sectional view of the trajectory assembly of FIG.17 .

FIG. 19 illustrates an exemplary secondary guide.

FIGS. 20-21 illustrate an exemplary method of planning an orthopaedicprocedure.

FIG. 22 illustrates a perspective view of an exemplary trajectoryassembly positioned relative to adjacent bones.

FIG. 23 illustrates an end view of the trajectory assembly of FIG. 22 .

FIG. 24 illustrates a sectional view of arm members of the trajectoryassembly of FIG. 23 .

FIG. 25 illustrates a perspective view of a secondary guide coupled tothe trajectory assembly of FIG. 22 .

FIG. 26 illustrates an end view of the trajectory assembly of FIG. 25 .

FIG. 27 illustrates a sectional view of the trajectory assembly of FIG.26 .

FIG. 28 illustrates side view of a cutting guide positioned relative toone of the bones of FIG. 25 .

FIG. 29 illustrates an end view of the cutting guide of FIG. 28 .

FIG. 30 illustrates side view of another cutting guide positionedrelative to one of the bones of FIG. 28 .

FIG. 31 illustrates resection surfaces of the bone of FIG. 28 .

FIG. 32 illustrates a perspective view of another exemplary trajectoryassembly positioned relative to adjacent bones.

FIG. 33 illustrates a perspective view of arm members of the trajectoryassembly of FIG. 32 .

FIG. 34 illustrates a perspective view of a secondary guide coupled tothe trajectory assembly of FIG. 32 .

FIG. 35 illustrates an end view of the trajectory assembly of FIG. 34 .

FIG. 36 illustrates a sectional view of the trajectory assembly of FIG.35 .

FIG. 37 illustrates a perspective view of a cutting guide positionedrelative to one of the bones of FIG. 34 .

FIG. 38 illustrates a perspective view of the cutting guide of FIG. 37and a resection.

FIG. 39 illustrates a side view of an implant positioned relative toadjacent bones.

FIG. 40 illustrates a side view of the implant secured to the adjacentbones of FIG. 39 .

Like reference numbers and designations in the various drawings indicatelike elements.

DETAILED DESCRIPTION

This disclosure relates to surgical devices and methods for repairingbone defects. The instrumentation and systems described herein may becapable of dimensioning or otherwise preparing a defect surface at asurgical site, including resecting bone or other tissue.

The disclosed planning systems and methods may be utilized to determineresection characteristics and sufficiency of contact surfaces to promotebone fusion and stability. The surgeon or assistant may interact withthe disclosed planning systems to set and adjust the resectioncharacteristics, including adjusting resection planes associated withthe selected bone models. The disclosed planning systems and methods maypresent the surgeon with parameters associated with the specifiedresection planes and other characteristics, including parametersassociated with a contact area between the adjacent resection surfaces,cortical and cancellous coverage, and shortening of the respectivebones. The surgeon may interact with the planning system to determinesuitable bone contact at different resection depths and any effects ofthe resections on limb alignment and shortening. Aspects of a surgicalplan can be established based on the parameters, including varioussettings and dimensions associated with instrumentation to prepare asurgical site. The disclosed trajectory assemblies may be utilized toestablish a precise trajectory of guide members in a manner thatsubstantially conforms to an associated surgical plan.

An assembly for preparation of a surgical site according to animplementation of the present disclosure includes, inter alia, atrajectory guide including a guide body and at least one arm membercoupled to the guide body. The guide body may include a guide passageextending along a passage axis. The at least one arm member may bemoveable relative to the guide body to set a trajectory of a first guidepin insertable through the guide passage relative to bone. A secondaryguide may include a main body having at least one aperture. The at leastone aperture may be dimensioned to at least partially receive a secondguide pin along an aperture axis. The secondary guide may be coupled tothe guide body such that the aperture axis may be offset from thepassage axis.

In a further implementation, the aperture axis may be substantiallyparallel to the passage axis.

In a further implementation, the main body may extend along a guideaxis. The at least one aperture may include a first row of aperturesdistributed about the guide axis.

In a further implementation, the at least one aperture may include asecond row of apertures distributed about the guide axis. The second rowof apertures may be outward of the first row of apertures relative tothe guide axis.

In a further implementation, each aperture of the first row of aperturesmay be substantially circumferentially aligned with a respectiveaperture of the second row of apertures relative to the guide axis.

In a further implementation, the main body may include a sleeve portionand a flange portion extending outwardly from a perimeter of the sleeveportion. The at least one aperture may be established along the flangeportion. The sleeve portion may have a sleeve passage dimensioned to atleast partially receive a proximal end portion of the guide body.

In a further implementation, the trajectory guide may include anabutment along an outer periphery of the guide body. The secondary guidemay be translatable along the passage axis to engage the abutment suchthat relative movement between the secondary guide and guide body may belimited relative to the passage axis.

In a further implementation, the trajectory guide may include a firstinterface feature along the guide body. The secondary guide may includea second interface feature along the sleeve portion. The first interfacefeature may be dimensioned to engage with the second interface featureto limit relative rotation between the guide body and the secondaryguide.

In a further implementation, the first interface feature may be aprotrusion extending outwardly from the outer periphery of the guidebody. The second interface feature may include at least one groove alongthe sleeve passage of the sleeve portion. The protrusion may beinsertable in the at least one groove to limit relative rotation betweenthe guide body and the secondary guide.

In a further implementation, the at least one groove may include anarray of grooves distributed along the sleeve passage of the sleeveportion. The protrusion may be insertable within a selected one of thegrooves to set a circumferential position of the at least one aperturerelative to the passage axis.

A system for planning an orthopaedic procedure according to animplementation of the present disclosure includes, inter alia, acomputing device including a processor coupled to a memory. Theprocessor may be configured to execute a planning environment includinga display module, a spatial module and a comparison module. The memorymay be configured to store a plurality of bone models including a firstbone model and a second bone model. The display module may be configuredto display the first bone model and the second bone model in a graphicaluser interface. The spatial module may be configured to establish afirst resection surface of the first bone model according to a firstreference plane. The spatial module may be configured to establish asecond resection surface of the second bone model along a secondreference plane. The spatial module may be configured to position thefirst resection surface in contact with the second resection surfacealong a contact region. The comparison module may be configured todetermine a contact area ratio. The contact area ratio may be defined asa first area of the first resection surface along the contact regiondivided by a second area of the second resection surface. The comparisonmodule may be configured to generate a first indicator in response toone or more predetermined criteria being met, the one or morepredetermined criteria including the contact area ratio meeting a firstpredefined threshold.

In a further implementation, the first area may be less than the secondarea. The first predefined threshold may be greater than or equal to0.4.

In a further implementation, the comparison module may be configured todetermine a contact to resection ratio. The contact to resection ratiomay be defined as the first area of the first resection surface alongthe contact region divided by the first area. The one or morepredetermined criteria may include the contact to resection ratio beinggreater than or equal to 0.75.

In a further implementation, the comparison module may be configured tocause the display model to display the first indicator in the graphicaluser interface in response to the one or more predetermined criteriabeing met.

In a further implementation, the comparison module may be configured tocause the display model to display a value of the contact area ratio inthe graphical user interface.

In a further implementation, the first bone model may be associated witha talus. The second bone model may be associated with a tibia.

In a further implementation, the spatial module may be configured tocause relative movement between the first resection surface and thesecond resection surface along the contact region in response to userinteraction. The comparison module may be configured to update a valueof the contact area ratio in response to the relative movement.

In a further implementation, the spatial module may be configured to seta position of the first reference plane with respect to the first bonemodel in response to user interaction. The spatial module may beconfigured to set a position of the second reference plane with respectto the second bone model in response to user interaction.

In a further implementation, the display module may be configured todisplay in a first display window of the graphical user interface thefirst and second bone models relative to a first image plane. Thedisplay module may be configured to set the first image plane to beparallel to the first and second reference planes such that the contactregion is displayed along the first image plane in the first displaywindow.

In a further implementation, the display module may be configured todisplay a visual contrast between the contact region and a remainder ofthe first and second resection surfaces that excludes the contactregion.

In a further implementation, the comparison module may be configured todetermine a set of values of the contact area ratio that may beassociated with different positions of the first bone model relative tothe second bone model along the contact region. Values in the set ofvalues of the contact area ratio may correspond to respective directionsfrom a contact axis intersecting the contact region. The display modulemay be configured to display a first directional indicator extending ina first direction relative to the contact axis. The first direction maybe associated with a maximum value of the set of values of the contactarea ratio.

In a further implementation, the spatial module may be configured toestablish a first outer perimeter and a first inner perimeter of thefirst bone model along the first reference plane. The first inner andouter perimeters may be associated with respective first inner and outerprofiles of a cortical wall associated with the first bone model. Thefirst inner perimeter may be associated with a first cancellous area ofthe first bone model. The first cancellous area may correspond to anarea along the first reference plane surrounded by the first innerperimeter. The spatial module may be configured to establish a secondouter perimeter and a second inner perimeter of the second bone modelalong the second reference plane. The second inner and outer perimetersmay be associated with respective second inner and outer profiles of acortical wall associated with the second bone model. The second innerperimeter may be associated with a second cancellous area of the secondbone model. The second cancellous area may correspond to an area alongthe second reference plane surrounded by the second inner perimeter. Thecomparison module may be configured to determine a cancellous coverageratio. The cancellous coverage ratio may be defined as an area ofoverlap between the first and second cancellous areas divided by thefirst cancellous area. The comparison module may be configured togenerate a second indicator in response to the cancellous coverage ratiomeeting a second predefined threshold.

In a further implementation, the second predefined threshold may beequal to or greater than 0.75.

In a further implementation, the spatial module may be configured todetermine a first cortical area and a second cortical area. The firstcortical area may correspond to an area between the first inner andouter perimeters along the contact region. The second cortical area maycorrespond to an area between the second inner and outer perimetersalong the contact region. The comparison module may be configured todetermine a cortical coverage area. The cortical coverage ratio may bedefined as an area of overlap between the first and second corticalareas divided by the first cortical area. The comparison module may beconfigured to generate a third indicator in response to the corticalcoverage ratio meeting a third predefined threshold.

In a further implementation, the third predefined threshold may be equalto or greater than 0.03.

In a further implementation, one of the first and second bone models maybe associated with a talus. Another one of the first and second bonemodels may be associated with a tibia.

In a further implementation, the first bone model may be associated witha talus. The second bone model may be associated with a tibia.

In a further implementation, the spatial module may be configured toestablish a first outer perimeter and a first inner perimeter of thefirst bone model along the first reference plane. The first inner andouter perimeters may be associated with respective first inner and outerprofiles of a cortical wall associated with the first bone model. Thespatial module may be configured to determine a first cortical area anda first boundary area. The first cortical area may correspond to an areabetween the first inner and outer perimeters along the contact region.The first boundary area may correspond to the area between the firstinner and outer perimeters. The comparison module may be configured todetermine a cortical support ratio. The cortical support ratio may bedefined as the first cortical area divided by the first boundary area.The one or more predetermined criteria may include the cortical supportratio being greater than or equal to 0.50.

In a further implementation, the spatial module may be configured toestablish a second outer perimeter and a second inner perimeter of thesecond bone model along the second reference plane. The second inner andouter perimeters may be associated with respective second inner andouter profiles of a cortical wall associated with the second bone model.The spatial module may be configured to determine a second boundaryarea. The second boundary area may correspond to the area between thesecond inner and outer perimeters. The spatial module may be configuredto establish at least four localized support regions along the firstboundary area. The comparison module may be configured to generate asupport indicator in response to a predefined support threshold beingmet. The predefined support threshold may be defined as a quantity ofthree localized support regions in which contact between the first andsecond boundary areas is established.

In a further implementation, the spatial module may be configured todetermine a first distance along a longitudinal axis between a first endand a second end of the second bone model. The spatial module may beconfigured to determine a second distance along the longitudinal axisbetween the second reference plane and the second end of the second bonemodel. The comparison module may be configured to determine a lengthratio in response to setting a position of the second reference plane.The length ratio may be defined as a ratio of the second distancedivided by the first distance. The comparison module may be configuredto generate a fourth indicator in response to the length ratio beingless than a predefined length threshold.

In a further implementation, the predefined length threshold may be lessthan or equal to 0.01.

In a further implementation, the spatial module may be configured todetermine a first trajectory associated with a first guide pin and asecond trajectory associated with a second guide pin in response to theone or more predetermined criteria being met. The first and secondtrajectories may be associated with respective first and secondpositions along one of the first and second bone models relative to thecontact region.

In a further implementation, the comparison module may be configured togenerate one or more settings associated with a trajectory assemblybased on the first and second trajectories.

In a further implementation, the memory may be configured to store atleast one implant model. The spatial module may be configured toposition the at least one implant model relative to the first and secondbone models in response to user interaction. The spatial module may beconfigured to determine one or more overlapping volumes between the atleast one implant model and the first and second bone models. Thedisplay module may be configured to display the at least one implantmodel in the graphical user interface. The display module may beconfigured to display a visual contrast between the one or moreoverlapping volumes and a remainder of the volumes of the first andsecond bone models that excludes the one or more overlapping volumes.

In a further implementation, the spatial module may be configured togenerate an iteration of the first and second bone models that excludesthe one or more overlapping volumes. The display module may beconfigured to display the at least one implant model positioned relativeto the iteration of the first and second bone models.

A method of performing an orthopaedic procedure according to animplementation of the present disclosure includes, inter alia, selectinga first bone model and a second bone model from a plurality of bonemodels. The method may include displaying the first and second bonemodels in a graphical user interface such that a first articular surfaceof the first bone model opposes a second articular surface of the secondbone model. The method may include setting a first reference plane inthe graphical user interface to establish a first resection surface ofthe first bone model. The method may include setting a second referenceplane in the graphical user interface to establish a second resectionsurface of the second bone model. The method may include generating afirst iteration of the first and second bone models that may excluderespective volumes of the first and second bone models between the firstand second reference planes and the first and second articular surfacesof the first and second bone models. The method may include positioningthe first resection surface in contact with the second resection surfaceto establish a contact region. The method may include displaying thefirst iteration of the first and second bone models along the contactregion in the graphical user interface. The method may includedetermining a contact area ratio. The contact area ratio may be definedas a first area of the first resection surface along the contact regiondivided by a second area of the second resection surface. The method mayinclude displaying at least one indicator in the graphical userinterface associated with the contact area ratio in response to meetingone or more predetermined criteria.

In a further implementation, the first bone model may be associated witha talus. The second bone model may be associated with a tibia.

In a further implementation, the at least one indicator may include avalue of the contact area ratio.

In a further implementation, the step of displaying the at least oneindicator may occur in response to meeting one or more predeterminedcriteria. The one or more predetermined criteria may include the contactarea ratio meeting a first predefined threshold.

In a further implementation, the first area may be less than the secondarea. The first predefined threshold may be greater than or equal to0.4.

In a further implementation, the step of displaying the first iterationof the first and second bone models along the contact region may includedisplaying a visual contrast between the contact region and a remainderof the first and second resection surfaces that excludes the contactregion.

In a further implementation, the step of determining the contact arearatio may include determining a set of values of the contact area ratioassociated with different positions of the first resection surfacerelative to the second resection surface along the contact region.Values in the set of values of the contact area ratio may correspond torespective directions along the contact region. The at least oneindicator may include a first directional indicator associated with amaximum value of the set of values of the contact area ratio. The stepof displaying the at least one indicator may include displaying thefirst directional indicator relative to the contact region.

In a further implementation, the method includes moving the first bonemodel in a second direction relative to the first bone model along thecontact region. The second direction may be substantially aligned with afirst direction corresponding to the first directional indicator.

In a further implementation, the method includes determining a firstcortical area along the first resection surface. The first cortical areamay be associated with cortical bone. The method may include determininga second cortical area along the second resection surface. The secondcortical area may be associated with cortical bone. The first corticalarea may be less than the second cortical area. The method may includedetermining a cortical coverage ratio. The cortical coverage ratio maybe defined as an area of overlap between the first and second corticalareas along the contact region divided by the first cortical area. Theone or more predetermined criteria may include the cortical coverageratio meeting a second predefined threshold.

In a further implementation, the second predefined threshold may begreater than or equal to 0.03.

In a further implementation, the first bone model may be associated witha talus. The second bone model may be associated with a tibia.

In a further implementation, the method includes determining a firstcancellous area along the first resection surface. The first cancellousarea may be associated with cancellous bone. The method may includedetermining a second cancellous area along the second resection surface.The second cancellous area may be associated with cancellous bone. Thefirst cancellous area may be less than the second cancellous area. Themethod may include determining a cancellous coverage ratio. Thecancellous coverage ratio may be defined as an area of overlap betweenthe first and second cancellous areas along the contact region dividedby the first cancellous area. The one or more predetermined criteria mayinclude the cancellous coverage ratio meeting a third predefinedthreshold.

In a further implementation, the third predefined threshold may begreater than or equal to 0.75.

In a further implementation, the first bone model may be associated witha talus. The second bone model may be associated with a tibia.

In a further implementation, the second bone model may be associatedwith a long bone. The method may include determining a first distancealong a longitudinal axis between a first end and a second end of thesecond bone model. The method may include determining a second distancealong the longitudinal axis between the second reference plane and thesecond end of the second bone model. The method may include determininga length ratio. The length ratio may be defined as a ratio of the seconddistance divided by the first distance. the step of displaying the atleast one indicator may occur in response to meeting one or morepredetermined criteria. The one or more predetermined criteria mayinclude the length ratio meeting a predefined length threshold.

In a further implementation, the predefined length threshold may be lessthan or equal to 0.01.

In a further implementation, the method includes determining a firsttrajectory associated with a first guide pin and a second trajectoryassociated with a second guide pin in response to the contact area ratiomeeting a first predefined threshold. The first and second trajectoriesmay be associated with respective first and second positions along oneof the first and second bone models relative to the contact region. Themethod may include generating one or more settings associated with atrajectory assembly based on the first and second trajectories.

In a further implementation, the trajectory assembly may include atrajectory guide and a secondary guide coupled to the trajectory guide.The method may include configuring the trajectory guide according to theone or more settings. the method may include moving the trajectory guideinto abutment with a bone. The bone may be associated with a respectiveone of the first and second bone models. the method may includepositioning the first guide pin into the bone with the trajectory guideaccording to the first trajectory. The method may include positioningthe second guide pin into the bone with the trajectory guide accordingto the second trajectory.

In a further implementation, the trajectory guide may include a guidebody and at least one arm member coupled to the guide body. The guidebody may include a guide passage that at least partially receives thefirst guide pin along a passage axis to establish the first trajectory.The step of configuring the trajectory guide may include moving the atleast one arm member from a first position to a second position relativeto the guide body. The secondary guide may include a main body having atleast one aperture that at least partially receives the second guide pinalong an aperture axis to establish the second trajectory. The secondaryguide may be coupled to the guide body such that the aperture axis maybe offset from the passage axis.

In a further implementation, the secondary guide may be moveablerelative to a longitudinal axis of the trajectory guide. The method mayinclude configuring the secondary guide according to the one or moresettings, which may include setting a position of the secondary guiderelative to the longitudinal axis to establish the second trajectoryrelative to the first trajectory.

In a further implementation, the method includes positioning a firstcutting guide along the first and second guide pins. The first cuttingguide may establish a resection plane. The resection plane may beassociated with one of the first and second reference planes. The methodmay include resecting a portion of the bone along the resection plane toestablish a resection surface of the bone.

In a further implementation, the bone may be a first bone associatedwith the first bone model. The first bone may be opposed to a secondbone associated with the second bone model. The method may includedetermining a third trajectory associated with a third guide pin and afourth trajectory associated with a fourth guide pin in response to thecontact area ratio meeting the first predefined threshold. The third andfourth trajectories may be associated with respective third and fourthpositions along the second bone model relative to the contact region.The method may include generating one or more settings associated withthe trajectory assembly based on the third and fourth trajectories. Themethod may include moving the trajectory guide into abutment with thesecond bone. The method may include positioning the third guide pin intothe second bone with the trajectory guide according to the thirdtrajectory. The method may include positioning the fourth guide pin intothe second bone with the trajectory guide according to the fourthtrajectory. The method may include resecting a portion of the secondbone associated according to the second reference plane to establish aresection surface of the second bone.

In a further implementation, the method includes moving resectionsurfaces of the first and second bones into abutment. The method mayinclude positioning an implant along the first and second bonessubsequent to the step of moving the resection surfaces of the first andsecond bones into abutment.

In a further implementation, the method includes selecting an implantmodel from a plurality of implant models. The method may includepositioning the implant model relative to the first and second bonemodels subsequent to establishing the contact region. The method mayinclude determining one or more overlapping volumes between the selectedimplant model and the first and second bone models. The method mayinclude displaying the selected implant model in the graphical userinterface, which may include displaying a visual contrast between theone or more overlapping volumes and a remainder of the volumes of thefirst and second bone models that excludes the one or more overlappingvolumes.

In a further implementation, the method includes generating a seconditeration of the first and second bone models that excludes the one ormore overlapping volumes. The method may include repeating the step ofdetermining the one or more overlapping volumes for the second iterationof the first and second bone models. The method may include repeatingthe step of displaying the selected implant model for the seconditeration of the first and second bone models.

In a further implementation, the first bone may be a talus. The secondbone may be a tibia.

A method of performing an orthopaedic procedure according to animplementation of the present disclosure includes, inter alia,configuring a trajectory guide. The trajectory guide may include a guidebody and at least one arm member coupled to the guide body. The guidebody may include a guide passage extending along a passage axis. Themethod may include moving the at least one arm member from a firstposition to a second position relative to the guide body to establish afirst trajectory along the passage axis. The method may includeconfiguring a secondary guide. The secondary guide may include a mainbody having at least one aperture extending along an aperture axis. Themethod may include coupling the secondary guide to the guide body toestablish a second trajectory along the aperture axis. The aperture axismay be offset from the passage axis. The method may include moving thetrajectory guide into abutment with bone. The method may includepositioning a first guide pin through the guide passage and then intothe bone according to the first trajectory. The method may includepositioning a second guide pin through the at least one aperture andthen into the bone according to the second trajectory.

In a further implementation, the step of configuring the secondary guideincludes moving the main body of the secondary guide relative to alongitudinal axis of the trajectory guide such that the at least oneaperture moves from a first circumferential position to a secondcircumferential position relative to the longitudinal axis.

FIG. 1 illustrates an exemplary planning system 20 that may be utilizedfor planning surgical procedures. The system 20 may be used for planningorthopaedic procedures, including pre-operatively, intra-operativelyand/or post-operatively to create, edit, execute and/or review surgicalplans.

The system 20 may include a host computer 21 and one or more clientcomputers 22. The host computer 21 may be configured to execute one ormore software programs. In some implementations, the host computer 21 ismore than one computer jointly configured to process softwareinstructions serially or in parallel.

The host computer 21 may be in communication with one or more networkssuch as a network 23 comprised of one or more computing devices. Thenetwork 23 may be a private local area network (LAN), a private widearea network (WAN), the Internet, or a mesh network, for example.

The host computer 21 and each client computer 22 may include one or moreof a computer processor, memory, storage means, network device and inputand/or output devices and/or interfaces. The input devices may include akeyboard, mouse, etc. The output device may include a monitor, speakers,printers, etc. The memory may, for example, include UVPROM, EEPROM,FLASH, RAM, ROM, DVD, CD, a hard drive, or other computer readablemedium which may store data and/or other information relating to theplanning techniques disclosed herein. The host computer 21 and eachclient computer 22 may be a desktop computer, laptop computer, smartphone, tablet, or any other computing device. The interface mayfacilitate communication with the other systems and/or components of thenetwork 23.

Each client computer 22 may be configured to communicate with the hostcomputer 21 directly via a direct client interface 24 or over thenetwork 23. The client computers 22 may be configured to execute one ormore software programs, such as a various surgical tools. The planningpackage may be configured to communicate with the host computer 21either over the network 23 or directly through the direct clientinterface 24. In another implementation, the client computers 22 areconfigured to communicate with each other directly via a peer-to-peerinterface 25.

Each client computer 22 may be operable to access and locally and/orremotely execute a planning environment 26. The planning environment 26may be a standalone software package or may be incorporated into anothersurgical tool. The planning environment 26 may provide a display orvisualization of one or more bone models and related images and one ormore implant models via one or more graphical user interfaces (GUI).Each bone model, implant model, and related images and other informationmay be stored in one or more files or records according to a specifieddata structure.

The system 20 may include at least one storage system 27, which may beoperable to store or otherwise provide data to other computing devices.The storage system 27 may be a storage area network device (SAN)configured to communicate with the host computer 21 and/or the clientcomputers 22 over the network 23, for example. In implementations, thestorage system 27 may be incorporated within or directly coupled to thehost computer 21 and/or client computers 22. The storage system 27 maybe configured to store one or more of computer software instructions,data, database files, configuration information, etc.

In some implementations, the system 20 is a client-server architectureconfigured to execute computer software on the host computer 21, whichis accessible by the client computers 22 using either a thin clientapplication or a web browser executing on the client computers 22. Thehost computer 21 may load the computer software instructions from localstorage, or from the storage system 27, into memory and may execute thecomputer software using the one or more computer processors.

The system 20 may include one or more databases 28. The databases 28 maybe stored at a central location, such as the storage system 27. Inanother implementation, one or more databases 28 may be stored at thehost computer 21 and/or may be a distributed database provided by one ormore of the client computers 22. Each database 28 may be a relationaldatabase configured to associate one or more bone models 29 and one ormore implant models 30 to each other and/or a surgical plan 31. Eachsurgical plan 31 may be associated with a respective patient. Each bonemodel 29, implant model 30 and surgical plan 31 may be assigned a uniqueidentifier or database entry. The database 28 may be configured to storedata corresponding to the bone models 29, implant models 30 and surgicalplans 31 in one or more database records or entries, and/or may beconfigured to link or otherwise associate one or more filescorresponding to each respective bone model 29, implant model 30 andsurgical plan 31. Bone models 29 stored in the database(s) 28 maycorrespond to respective patient anatomies from prior surgical cases,and may be arranged into one or more predefined categories such as sex,age, ethnicity, defect category, procedure type, etc.

Each bone model 29 may include information obtained from one or moremedical devices or tools, such as a computerized tomography (CT),magnetic resonance imaging (MRI) machine and/or X-ray machine, thatobtains one or more images of a patient. The bone model 29 may includeone or more digital images and/or coordinate information relating to ananatomy of the patient obtained or derived from the medical device(s).Each implant model 30 may include coordinate information associated witha predefined design. The planning environment 26 may incorporate and/orinterface with one or more modeling packages, such as a computer aideddesign (CAD) package, to render the models 29, 30 as two-dimensional(2D) and/or three-dimensional (3D) volumes or constructs.

The predefined design may correspond to one or more components. Theimplant models 30 may correspond to implants and components of variousshapes and sizes. Each implant may include one or more components thatmay be situated at a surgical site including screws, anchors and/orgrafts. Each implant model 30 may correspond to a single component ormay include two or more components that may be configured to establishan assembly. Each bone model 29 and implant model 30 may correspond to2D and/or 3D geometry, and may be utilized to utilized to generate awireframe, mesh and/or solid construct in a display.

Each surgical plan 31 may be associated with one or more of the bonemodels 29 and implant models 30. The surgical plan 31 may include one ormore revisions to bone model 29 and information relating to a positionof an implant model 30 relative to the original and/or revised bonemodel 29. The surgical plan 31 may include coordinate informationrelating to the revised bone model and a relative position of theimplant model 30 in predefined data structure(s). Revisions to each bonemodel 29 and surgical plan 31 may be stored in the database 28automatically and/or in response to user interaction with the system 20.

One or more surgeons and other users may be provided with a planningenvironment 26 via the client computers 22 and may simultaneously accesseach bone model 29, implant model 30 and surgical plan 31 stored in thedatabase(s) 28. Each user may interact with the planning environment 26to create, view and/or modify various aspects of the surgical plan 31.Each client computer 22 may be configured to store local instances ofthe bone models 29, implant models 30 and/or surgical plans 31, whichmay be synchronized in real-time or periodically with the database(s)28. The planning environment 26 may be a standalone software packageexecuted on a client computer 22 or may be provided as one or moreservices executed on the host computer 21, for example.

FIG. 2 illustrates an exemplary fusion planning system 120 for planninga surgical procedure. The system 120 may be utilized to plan andimplement various orthopaedic and other surgical procedures, such as anarthroplasty to repair a joint. The system 120 may be utilized inplanning a resection of one or more bones that may be positioned forfusion. The system 120 may be utilized in planning placement of animplant, which may be utilized for fusion of resected bones such as atibia and talus in an ankle repair. Although the planning systems andmethods disclosed herein primarily refer to repair of an ankle, itshould be understood that the planning system 120 may be utilized in therepair of other locations of the patient and other surgical proceduresincluding repair of other joints such as a shoulder, wrist, hand, hip orknee, and including repair of fractures.

The system 120 may include a computing device 132 including at least oneprocessor 133 coupled to memory 134. The computing device 132 caninclude any of the computing devices disclosed herein, including thehost computer 21 and/or client computer 22 of FIG. 1 . The processor 133may be configured to execute a planning environment 126 for creating,editing, executing and/or reviewing one or more surgical (e.g.,pre-operative) plans 131 during pre-operative, intra-operative and/orpost-operative phases of a surgery.

The planning environment 126 may include at least a data module 135, adisplay module 136, a spatial module 137 and a comparison module 138.Although four modules are shown, it should be understood that fewer ormore than four modules may be utilized and/or one or more of the modulesmay be combined to provide the disclosed functionality.

The data module 135 may be configured to access, retrieve and/or storedata and other information in the database(s) 128 corresponding to oneor more bone model(s) 129, implant model(s) 130 and/or surgical plan(s)131. The data and other information may be stored in one or moredatabases 128 as one or more records or entries 139. In someimplementations, the data and other information may be stored in one ormore files that are accessible by referencing one or more objects ormemory locations references by the records or entries 139.

The memory 134 may be configured to access, load, edit and/or storeinstances of one or more bone models 129, implant models 130 and/orsurgical plans 131 in response to one or more commands from the datamodule 135. The data module 135 may be configured to cause the memory134 to store a local instance of the bone model(s) 129, implant model(s)130 and/or surgical plan(s) 131 which may be synchronized with records139 in the database(s) 128.

The display module 136 may be configured to display data and otherinformation relating to one or more surgical plans 131 in at least onegraphical user interface (GUI) 142. The computing device 132 may becoupled to a display device 140. The display module 136 may beconfigured to cause the display device 140 to display information in theuser interface 142. A surgeon or other user may interact with the userinterface 142 via the planning environment 126 to create, edit, executeand/or review one or more surgical plans 131.

Referring to FIG. 3 , with continuing reference to FIG. 2 , the userinterface 142 may include one or more display windows 144 and one ormore objects 146. The objects 146 may include graphics such as menus,tabs and buttons accessible by user interaction, such as tabs 146T,buttons 146B, 146V, drop-down lists 146L, menus 146M, entry fields 146E(FIGS. 6 and 8 ), directional indicators 146D, 146R and graphics 146G(see, e.g., FIGS. 5-6 ). Geometric objects including selected bonemodel(s) 129 and implant model(s) 130 (see, e.g., FIG. 12 ) and otherinformation relating to the surgical plan 131 may be displayed in one ormore of the display windows 144.

The implant model 130 may include one or more components. Exemplaryimplants may include bone plates configured to interconnect adjacentbones (see, e.g., FIG. 12 ) or bone fragments, base plates coupled to anarticulation member, etc. The articulation member may have an articularsurface dimensioned to mate with an articular surface of an opposed boneor implant.

The display module 136 may be configured to display one or more selectedbone models 129 and/or one or more selected implant models 130 (see,e.g., FIGS. 9 and 12 ) in the display windows 144. The display module136 may be configured such that the selected bone model 129 and/orselected implant model 130 may be selectively displayed and hidden(e.g., toggled) in one or more of the display windows 144 in response touser interaction with the user interface 142, which may provide thesurgeon with enhanced flexibility in reviewing aspects of the surgicalplan 131.

The data module 135 may be configured to access a first bone model 129-1and a second bone model 129-1 from the database 128, which may occurautomatically or in response to user interaction with the user interface142. The data module 135 may be configured to store an instance of thefirst bone model 129-1 and second bone model 129-1 in the memory 134.The first bone model 129-1 and second bone model 129-2 may be associatedwith a joint. For example, one of the bone models 129 may be associatedwith a long bone such as a tibia, and another one of the bone models 129may be associated with an adjacent bone such as a tibia that cooperateto establish an ankle or another joint of a patient. In theimplementation of FIG. 3 , the second bone model 129-2 may be associatedwith a tibia, and the first bone model 129-1 may be associated with atalus. The display module 136 may be configured to display the firstbone model 129-1 and second bone model 129-2 in at least one of thedisplay windows 144 of the user interface 142.

The display windows 144 may include first and second display windows144-1, 144-2. Although a particular number of display windows 144 areillustrated, it should be understood that the user interface 142 may beconfigured with any number of display windows 144 in accordance with theteachings disclosed herein. The display windows 144-1, 144-2 may beconfigured to display a two-dimensional (2D) and/or three-dimensional(3D) representation of the selected bone models 129.

The first display window 144-1 may be configured to display the firstbone model 129-1 and second bone model 129-2 relative to each other. Thespatial module 137 may be configured to position the bone models 129-1,129-2 into contact with each other at a specified or defined positionand orientation, which may be according to user interaction with thewindow 144-1, menu 146M, and/or other objects 146 of the user interface142.

The surgeon or assistant may interact with the display window 144-1 oranother portion of the user interface 142 to move the selected bonemodel 129 and/or selected implant model 130 in 2D space (e.g., up, down,left, right) and/or 3D space (e.g., rotation, tilt, zoom, etc.), whichmay occur in response to interaction with the directional indicators146D, 146R.

The second display window 144-2 may be configured to display the firstbone model 129-1 and second bone model 129-2 in spaced relationshiprelative to each other. The surgeon or assistant may interact with thesecond display window 144-2 or another portion of the user interface 142to associate one or more landmarks L with the selected bone models 129.The landmarks L may include one or more points P along the anatomy(e.g., P1-P2) and one or more planes (e.g., L1-L4). Exemplary landmarksinclude a tibial axis, sagittal plane, coronal plane and transverseplane. In implementations, the spatial module 137 may be configured todetermine one or more landmarks L based on evaluating a profile of theselected bone model 129. The profile can be compared to one or moreprofiles of representative bones in the database 128.

Referring to FIG. 4 , with continuing reference to FIGS. 2-3 , the userinterface 142 may include third and fourth display windows 144-3, 144-4.The surgeon or assistant may interact with the display windows 144-3,144-4 or another portion of the user interface 142 to specify one ormore aspects of, or modifications to, the surgical plan 131. Themodifications may include one or more resection planes REF associatedwith a respective one of the bone models 129. The third display window144-3 may be configured to display each reference plane REF relative tothe respective bone model 129. The bone models 129-1, 129-2 may includerespective articular surfaces AS1, AS2 associated with a joint. Eachreference plane REF may be associated with a respective depth inwardfrom the respective articular surface AS1/AS2 of the bone model 129(e.g., 1 mm, 2 mm, 3 mm, 4 mm etc.). The reference planes REF may besubstantially perpendicular to a landmark L of the respective bone model129 (e.g., landmarks L1, L2 and reference planes REF1-REF8). For thepurposes of this disclosure, the terms “substantially,” “about” and“approximately” mean±5 percent of the stated value or relationshipunless otherwise indicated. One or more of the reference planes REF maybe transverse to another reference plane REF (e.g., reference plane REFSrelative to reference planes REF1-REF4).

The spatial module 137 may be configured to set a position of a firstreference plane REF with respect to the first bone model 129-1 inresponse to user interaction with the user interface 142. The spatialmodule 137 may be configured to set a position of a second referenceplane REF with respect to the second bone model 129-2 in response touser interaction with the user interface 142. For example, the surgeonor assistant may adjust a position (e.g., depth) and/or angle of aselected reference plane REF in response to user interaction with theuser interface 142. The surgeon or assistant may interact with one ofthe entry fields 146E to specify an offset or depth associated with thereference plane REF.

The spatial module 137 may be configured to generate a first iterationof respective first and second (e.g., resected) bone models 129-1′,129-2′. The bone models 129-1′, 129-2′ may exclude respective volumes ofthe bone models 129-1, 129-2 between the respective reference planes REFand articular surfaces AS1, AS2 of the bone models 129-1, 129-2, asillustrated in the fourth display window 144-4. The bone models 129-1′,129-2′ may be separate models or may be stored as one or more revisionsto the respective bone models 129-1, 129-2.

The spatial module 137 may be configured to establish a first resection(e.g., contact) surface S1 of the first bone model 129-1′ according to afirst reference plane REF (e.g., REF1-REF4) and may be configured toestablish a second resection (e.g., contact) surface S2 of the secondbone model 129-2′ along a second reference plane REF (e.g., REF5-REF8),as illustrated in the fourth display window 144-4. The first and secondresection surfaces S1, S2 of the bone models 129-1′, 129-2′ may beopposed relative to each other and may be positioned apart and/or inabutment in the display windows 144. The fourth display window 144-4 maybe dynamically linked to the third display window 144-3 such thatselection and/or adjustments to the respective reference plane REFassociated with the third display window 144-3 cause a position of therespective resection surface S1/S2 to change in the fourth displaywindow 144-4. The display module 136 may be configured to display theiteration of the bone models 129-1′, 129-2′ in the fourth display window144-4 in response to adjusting or otherwise setting the resection planesREF. The surgeon or assistant may interact with the user interface 142to obtain a visualization of resection depths, which may be adjustedprior to approval of the surgical plan 131.

The spatial module 137 may be configured to position the first resectionsurface S1 associated with the first bone model 129-1′ in contact withthe second resection surface S1 of associated with the second bone model129-2′ along a contact region CR. The contact region CR may be a regionof bone-to-bone contact between the resection surfaces S1, S2. Thecontact region CR may be continuous or may be discontinuous includingtwo or more localized regions of contact. The localized regions ofcontact may be separated by a space due to surface depression(s) orother contouring along the resection surfaces S1, S2.

The surgeon or assistant may interact with the directional indicators146D, 146R or another portion of the user interface 142 to adjust orotherwise setting a relative position between the bone models 129-1′,129-2′ along the contact region CR. The surgeon or assistant mayinteract with the user interface 142 to evaluate aspects of the bonemodels 129-1′, 129-2′ relative to the contact region CR and associatedreference planes REF.

Referring to FIG. 5 , with continuing reference to FIGS. 2 and 4 , thedisplay windows 144 can include fifth, sixth and seventh display windows144-5, 144-6, 144-7. The fifth display window 144-5 can be configured todisplay an isolated view of the iteration of the first bone model129-1′. The sixth display window 144-6 can be configured to display anisolated view of the iteration of the second bone model 129-2′.

The fifth, sixth and seventh display windows 144-5, 144-6, 144-7 may beassociated with respective fifth, sixth and seventh image (e.g.,viewing) planes IPS, IP6, IP7 (shown in dashed lines for illustrativepurposes). The fifth, sixth and/or seventh image planes IPS, IP6, IP7may be substantially parallel to each other. The display module 136 maybe configured to set the image planes IPS, IP6, IP7 to be substantiallyparallel to the specified or defined reference planes REF associatedwith the respective bone models 129-1′, 129-2′. The display module 136may be configured to display the resection surfaces S1, S2 and/orcontact region CR substantially parallel to the image planes IPS, IP6,IP7 of the respective display windows 144-5, 144-6, 144-7 such that theresection surfaces S1, S2 and/or contact region CR are displayed alongthe image planes IPS, IP6, IP7 of the respective display windows 144-5,144-6, 144-7. Utilizing the techniques disclosed herein, the resectionsurfaces S1, S2 may be presented substantially perpendicular to theuser, which may assist the surgeon in evaluating the defined resectionplanes REF (FIG. 4 ) and determining whether to implement one or morerevisions or adjustments to the resection planes REF and/or resectedbone models 129-1′, 129-2′.

Referring to FIG. 6 , with continuing reference to FIGS. 2 and 5 , theuser interface 142 may be configured to display an isolated view of theresection surfaces S1, S2 along the contact region CR in the seventhdisplay window 144-7. The contact region CR is shown in dashed lines forillustrative purposes. The user interface 142 may be configured todisplay the fourth display window 144-4 adjacent to the seventh displaywindow 144-7, which may be utilized by the surgeon or assistant to makeone or more adjustments to the relative positioning of the bone models129-1′, 129-2′ relative to the contact region CR, which may improve theability of the surgeon or assistant to evaluate the contact region CRand selected resection planes REF (FIG. 4 ).

The spatial module 137 may be configured to determine one or moreparameters associated with the contact region CR. The spatial module 137may be configured to determine a first area A1 of the first resectionsurface S1 and a second area A2 of the second resection surface S2. Thespatial module 137 may be configured to determine one or more localizedregions of the areas A1, A2, such as first and second cortical areasCO1, CO2, first and second cortical boundary areas CB1, CB2 and/or firstand second cancellous areas CA1, CA2 associated with the respectiveareas A1, A2. The cortical areas CO1, CO2 and cortical boundary areasCB1, CB2 may be associated with cortical bone. The cancellous areas CA1,CA2 may be associated with cancellous bone surrounded by a cortical wallof the cortical bone.

Various techniques may be utilized to determine the areas. The spatialmodule 137 may be configured to establish a first outer perimeter PO1and a first inner perimeter PH of the first bone model 129-1′ along therespective reference plane REF (FIG. 4 ), as illustrated in FIG. 5 . Thefirst inner and outer perimeters PI1, PO1 may be associated withrespective first inner and outer profiles of a cortical wall associatedwith the first bone model 129-1′. The first inner perimeter PH may beassociated with the first cancellous area CA1 of the first bone model129-1′. The first cancellous area CA1 may correspond to an area alongthe reference plane REF surrounded by the first inner perimeter PH. Thespatial module 137 may be configured to establish a second outerperimeter PO2 and a second inner perimeter PI2 of the second bone model129-2′ along the respective reference plane REF (FIG. 4 ), asillustrated in FIG. 5 . The second inner and outer perimeters PI2, PO2may be associated with respective second inner and outer profiles of acortical wall associated with the second bone model 129-2′. The secondinner perimeter PI2 may be associated with a second cancellous area CA2of the second bone model 129-2′. The second cancellous area CA2 maycorrespond to an area along the respective reference plane REFsurrounded by the second inner perimeter PI2. The first cortical areaCO1 may correspond to an area between the first inner and outerperimeters PH, PO1 along the contact region CR. The first corticalboundary area CB1 may correspond to the area between the first inner andouter perimeters PI1, PO1, inclusive of the first cortical area CO1. Thesecond cortical area CO2 may correspond to an area between the secondinner and outer perimeters PI2, PO2 along the contact region CR. Thesecond cortical boundary area CB2 may correspond to the area between thesecond inner and outer perimeters PI2, PO2, inclusive of the secondcortical area CO2. Defining the areas A1, A2, CA1, CA2, CO1, CO2 withrespect to the contact region CR can be utilized to omit portions of theresection surfaces S1, S2 that may not establish contact due tooverhang, underhang and/or other misalignment between the bone models129-1′, 129-2′. Defining the cortical boundary areas CB1, CB2 may beutilized to account for portions of the resection surfaces S1, S2 thatmay not establish contact along the contact region CR.

Various techniques may be utilized to determine the perimeters PI1, PI2,PO1, PO2 and associated areas A1, A2, CA1, CA2, CB1, CB2, CO1, CO2,including edge detection techniques based on one or more imagegradients. Other exemplary techniques may include positioning one ormore points along the bone resection surfaces S1, S2 in response to userinteraction with the user interface 142, which may be interconnected toestablish a perimeter associated with the respective area. One ofordinary skill in the art would understand how to program the spatialmodule 137 with logic to determine the various parameters including thePI1, PI2, PO1, PO2 and associated areas A1, A2, CA1, CA2, CB1, CB2, CO1,CO2, including one or more CAD tools, libraries, etc.

The comparison module 138 may be configured to determine a contact(e.g., coverage) area ratio CAR associated with the contact region CR.The contact area ratio CAR may be defined as the first area A1 of thefirst resection surface S1 along the contact region CR divided by thesecond area A2 of the second resection surface S2. The first area A1 maybe less than the second area A2. The following table illustratesexemplary contact area ratios CAR with respect to cut depth and surfacesareas of the first and second resection surfaces S1, S2, which may beassociated with adjacent bones such as a talus and tibia.

Surface Area (mm²) Cut Depth (mm) 1 × 1 1 × 2 1 × 3 2 × 1 2 × 2 2 × 3 3× 1 3 × 2 3 × 3 Talus 355.5 545.4 688.8 355.5 688.8 355.5 355.5 545.4688.8 Tibia 1163.1 1163.1 1158.4 1158.4 1158.4 1151.3 1151.3 1151.31151.3 Contact area 0.306 0.469 0.592 0.307 0.471 0.595 0.309 0.4740.598 ratio (CAR)

The system 120 may be configured to determine a portion of the firstarea A1 of the first resection surface S1 that establishes the contactregion CR. A contact to resection area ratio CRR may be defined as anarea of the first resection surface S1 along the contact region CRdivided by the first area A1 of the first resection surface S1. Inimplementations, the contact to resection area ratio CRR may be greaterthan or equal to 0.75, or more narrowly greater than or equal to 0.90,or more narrowly less than or equal to 1.0. The contact to resectionarea ratio CRR may be 1.0 such that an entirety of the first resectionsurface S1 contacts the second resection surface S2 to establish thecontact region CR. The first area A1 may be less than the second area A2such that a portion of the second resection surface S2 may not contactthe first resection surface S1.

The system 120 may be configured to determine other aspects associatedwith the contact area ratio CAR, including particular bone typesassociated with the bone models 129-1′, 129-2′ such as cortical bone andcancellous bone. The comparison module 138 may be configured todetermine a cancellous coverage ratio CCR. The cancellous coverage ratioCCR may be defined as an area of overlap between the first and secondcancellous areas CA1, CA2 divided by the first cancellous area CA1. Thecancellous coverage ratio CCR may be utilized to indicate whether bonesassociated with the resection surfaces S1, S2 along the contact regionCR are likely to achieve sufficient bone fusion, which may improvehealing of the patient.

The comparison module 138 may be configured to determine a corticalcoverage ratio COR. The cortical coverage ratio COR may be defined as anarea of overlap between the first and second cortical areas CO1, CO2divided by the first cortical area CO1. The cortical coverage ratio CORmay be utilized to indicate whether bones associated with the resectionsurfaces S1, S2 along the contact region CR are likely to achievesufficient support.

The system 120 may be configured to determine an amount of the firstcortical boundary area CB1 and/or an amount of the second corticalboundary area CB2 that establishes the contact region CR. The surgeonmay interact with the system 120 to evaluate whether or not the resectedload bearing bone(s) may provide sufficient support to the adjacentresected bone. The second resection surface S2 of the second bone model129-2 may sit on, or may otherwise be supported by, the first resectionsurface S1 of the first bone model 129-1 such that the first bone model129-1 may be associated with the load bearing bone and such that thesecond bone model 129-2 may be associated with the supported bone, orvice versa, which may depend on the surgical procedure associated withthe surgical plan 131.

A cortical support ratio CSR may be defined as the cortical area CO1/CO2divided by the respective cortical boundary area CB1/CB2. Inimplementations, the cortical support ratio CSR may be greater than orequal to 0.50, more narrowly greater than or equal to 0.75, or even morenarrowly greater than or equal to 0.90. The cortical support ratio CSRmay be less than or equal to 1.0. The cortical support ratio CSR may be1.0 such that an entirety of the cortical boundary area CB1/CB2 contactsthe adjacent resection surface S2/S1 to establish the contact region CRand associated cortical area CO1/CO2. The cortical support ratio CSRdisclosed herein may be utilized to establish an improved support orfoundation to the opposing resection surface S2/S1. The cortical supportratio CSR may be utilized in combination with an implant to provide theimproved support, including any of the implants disclosed herein.Improved support may be beneficial to patients having relatively smallerbones, lesser bone density, lesser bone quality, etc.

The comparison module 138 may be configured to cause the display module136 to display value(s) of one or more parameters associated with thecontact region CR in a graphic 146G or another portion of the userinterface 142. The graphic 146G may overlay or be arranged adjacent toone of the display windows 144 associated with the contact region CR,such as the seventh display window 144-7. Example parameters include thedetermined contact area ratio CAR and related parameters, such as theresection depth(s) associated with the respective reference planes REF(FIG. 4 ), first and second areas A1, A2, cortical areas CO1, CO2,cortical boundary areas CB1, CB2, cancellous areas CA1, CA2, cancellouscoverage ratio CCR, cortical coverage ratio COR, and/or cortical supportratio CSR.

The comparison module 138 may be configured to generate one or moreindicators PI in response to one or more predetermined criteria beingmet, including any of the predetermined criteria and/or thresholdsdisclosed herein. It should be understood that any of the indicatorsdisclosed herein may a separate indicator or may be combined with one ormore other indicators. The comparison module 138 may be configured togenerate the indicator(s) PI in response to the contact area ratio CARmeeting one or more predetermined criteria, such as one or morepredefined thresholds. The predefined thresholds may be configured orset in the system 120 according to various parameters, includingprocedure type, implant type, bone or joint type, bone quality, etc.,and may be set and/or adjusted by the surgeon or assistant.

Various indicators PI may be utilized, including textual and graphicalindicators. The indicators PI may include value indicators PV andthreshold (e.g., graphical) indicators PT. The indicators PI may includea first indicator PH associated with the contact area ratio CAR, asecond indicator PI2 associated with the cancellous coverage ratio CCR,and/or a third indicator PI3 associated with the cortical coverage ratioCOR. The indicators PI may include a value indicator PVC associated withthe cortical support ratio CSR (see also FIGS. 9-10 ).

The surgeon or assistant may interact with the user interface 142 todetermine whether or not the proposed surgical plan 131 may establishsufficient bone fusion between adjacent bones. The comparison module 138may be configured to cause the display module 136 to generate one ormore indicators PI in response to a percentage of the contact area ratioCAR, contact to resection ratio CRR, cancellous coverage ratio CCR,cortical coverage ratio COR and/or cortical support ratio CSR exceedingrespective predefined thresholds, as illustrated by the thresholdindicator PT. The threshold indicator PT may include various states,such as an UP arrow indicating that the predefined threshold(s) are met(e.g., FIGS. 5-6 ) and a DOWN arrow indicating that the predefinedthreshold(s) are not met (e.g., FIG. 8 ). Other example indicators PImay include a shading or color coding status of the contact region CR(e.g., green for being met and red for not being met).

The comparison module 138 may be configured to generate one or moreindicators PI (e.g., a first indicator) in response to the one or morepredetermined criteria being met, including the contact area ratio CARmeeting a first predefined threshold. The first predefined threshold maybe established by any values of the contact area ratio CAR disclosedherein. In implementations, the first predefined threshold may include acontact area ratio CAR that is greater than or equal to 0.4, or morenarrowly greater than or equal to 0.5. The first predefined thresholdmay include the contact area ratio CAR being greater than or equal to0.75, or more narrowly equal to 1.0 such that an entirety of the firstresection surface S1 contacts the second resection surface S2 (see,e.g., FIG. 7 ).

The comparison module 148 may be configured to generate one or moreindicators PI (e.g., a second indicator) in response to the one or morepredetermined criteria being met, including the cancellous coverageratio CCR meeting a second predefined threshold. The second predefinedthreshold may be established by any values of the cancellous coverageratio CCR disclosed herein. In implementations, the second predefinedthreshold(s) may include a cancellous coverage ratio CCR that is equalto or greater than 0.75, or more narrowly greater than or equal to 0.90.The second predefined threshold may include the cancellous coverageratio CCR being equal to 1.0 such that an entirety of the firstcancellous area CA1 contacts the second cancellous area CA2.

The comparison module 138 may be configured to generate one or moreindicators PI (e.g., a third indicator) in response to the one or morepredetermined criteria being met, including the cortical coverage ratioCOR meeting a third predefined threshold. The third predefined thresholdmay be established by any values of the cortical coverage ratio CORdisclosed herein. In implementations, the third predefined threshold mayinclude a cortical coverage ratio COR that is greater than or equal to0.03, or more narrowly greater than or equal to 0.05.

The comparison module 138 may be configured to generate one or moreindicators PI (e.g., fifth indicator) in response to the one or morepredetermined criteria being met, including the contact to resectionratio CRR meeting a fifth predefined threshold. The fifth predefinedthreshold may be established by any values of the contact to resectionratio CRR disclosed herein. In implementations, the fifth predefinedthreshold may include a contact to resection ratio CRR greater than orequal to 0.75, more narrowly greater than or equal to 0.90, or even morenarrowly equal to 1.0. In implementations, the comparison module 138 maybe configured to generate the one or more indicators PI (e.g., firstindicator) in response to the contact area ratio CAR meeting the firstpredefined threshold and/or the contact to resection ratio CRR meetingthe fifth predefined threshold.

The comparison module 138 may be configured to generate one or moreindicators PI (e.g., sixth indicator) in response to the one or morepredetermined criteria being met, including the cortical support ratioCSR meeting a sixth predefined threshold. The sixth predefined thresholdmay be established by any values of the cortical support ratio CSRdisclosed herein. In implementations, the sixth predefined threshold mayinclude a cortical support ratio CSR greater than or equal to 0.50, morenarrowly greater than or equal to 0.75, more narrowly greater than orequal to 0.90, or even more narrowly equal to 1.0. In implementations,the comparison module 138 may be configured to generate the one or moreindicators PI (e.g., first indicator) in response to the contact arearatio CAR meeting the first predefined threshold and/or the corticalsupport ratio CSR meeting the sixth predefined threshold. The indicatorsPI may include a value of the cortical support ratio CSR, as illustratedby the indicator PVC.

The comparison module 138 may be configured to cause the display module136 to display the indicator(s) PI in the user interface 142 in responseto the respective predefined threshold(s) and/or other predeterminedcriteria being met. The comparison module 138 may be configured to causethe display module 136 to display value indicators PV1-PV3, PVCassociated with respective values of the contact area ratio CAR,cortical coverage ratio COR, cancellous coverage ratio CCR and corticalsupport ratio CSR in the graphic 146G or another portion of the userinterface 142.

The display module 136 may be configured to display a visual contrastbetween the contact region CR and a remainder of the resection surfacesS1, S2 that excludes the contact region CR, illustrated by respectivegraphics R1, R2 in FIG. 7 . The visual contrast may be shown in adifferent shade and/or color than the remainder of the surface areas S1,S2 of the bone models 129-1, 129-2. The display module 136 may beconfigured to display a visual contrast between portions of the contactregion CR associated with cortical bone and cancellous bone along thecontact region CR, illustrated by respective graphics R1A, R1B. Thevisual contrast is shown as hatching in the display window 144-7 of FIG.7 for illustrative purposes. The user may select a button 146B in themenu 146M associated with the seventh display window 144-7 to togglebetween the views of the contact region CR of FIGS. 6 and 7 , which mayprovide the surgeon different perspectives of the contact region CR andrelated anatomy of the patient prior to approving or revising a surgicalplan 131.

Referring to FIG. 8 , with continuing reference to FIGS. 2 and 6 , thesurgeon or assistant may interact with the user interface 142 to causeone or more adjustments relating to the contact region CR and bonemodels 129-1′, 129-2′. The spatial module 137 may be configured to causerelative movement between the resection surfaces S1, S2 along thecontact region CR in response to user interaction with the userinterface 142. In implementations, the user may interact with thedirectional indicator 146D and/or 146R or directly with the bone models129-1′, 129-2′ in the display window 144-7 to cause relative movement.The second bone model 129-2′ may be moved in a direction DIR1, forexample, causing a change (e.g., decrease or increase) in the contactarea ratio CAR. The comparison module 138 may be configured to update avalue of the contact area ratio CAR, cancellous coverage ratio CCR,contact to resection ratio CRR, cortical coverage ratio COR and/orcortical support ratio CSR in response to the relative movement. Thevalues may be updated in the graphic 146G. The updated values may causea change in the status of the indicator PT based on whether or not thecontact area ratio CAR, cancellous coverage ratio CCR, contact toresection ratio CRR, cortical coverage ratio COR and/or cortical supportratio CSR meet the predetermined criteria, including any of thepredefined thresholds disclosed herein. The surgeon may evaluate theratios CAR, CCR, CRR, COR and/or CSR to determine suitable resectiondepths.

At least one of the bone models 129-1′, 129-2′ may be associated with acontact axis X intersecting the contact region CR. The contact axis Xmay extend through and may be perpendicular to the resection surfacesS1, S2. The comparison module 138 may be configured to determine a setof values of the contact area ratio CAR associated with differentpositions of the first bone model 129-1′ relative to the second bonemodel 129-2′ along the contact region CR, with values in the set ofvalues of the contact area ratio CAR corresponding to respective polarcoordinates or directions from the contact axis X. The comparison module138 may be configured to determine a maximum value of the set of valuesof the contact area ratio CAR in which contact is maintained between theresection surfaces S1, S2. Each value may be associated with arespective coordinate along the resection surface S1/S2 such that valuesmay be determined for at least some or substantially all relativepositions between the bone models 129-1′, 129-2′ in which contact alongthe resection surfaces S1, S2 is maintained. In implementations, valuesof the contact area ratio CAR for only small incremental changes inposition may be determined, such as a single change in position ordirection.

The display module 136 may be configured to display a first directionalindicator DA extending in a first direction relative to the contact axisX. The first direction may be associated with the maximum value of thecontact area ratio CAR determined by the comparison module 138.Exemplary directional indicators DA-1, DA-2, DA-3 are illustrated inFIG. 8 , with directional indicators DA-2, DA-3 shown in dashed lines toillustrate indicators DA that may associated with other exemplarypositions between the bone models 129-1′, 129-2′. In implementations,the directional indicator DA may be a vector from the contact axis X.The user may infer an amount and direction of suggested movement basedon the vector that may result in an increase a value of the contact arearatio CAR, which may promote improved bone fusion between the resectionsurfaces S1, S2.

Referring to FIG. 9 , with continuing reference to FIGS. 2 and 6 , thesystem 120 may be configured to determine other aspects associated withthe boundary areas CB1, CB2 of the bone models 129-1, 129-2. The spatialmodule 137 may be configured to establish one or more localized supportregions LSR along one of the boundary areas CB1, CB2, such as theboundary area CB1. The localized support regions LSR are separate anddistinct from each other. In the implementation of FIG. 9 , the spatialmodule 137 establishes at least four localized support regions LSR(indicated at LSR1-LSR4). The localized support regions LSR1-LSR4 may bespaced apart from each other along a perimeter of the boundary area CB1.Although four localized support regions LSR are illustrated in FIG. 9 ,it should be understood that fewer or more than four localized supportregions LSR may be established utilizing the techniques disclosedherein, including two or three localized support regions LSR. Thespatial module 137 may be configured to determine whether or not contactbetween the boundary areas CB1, CB2 is established at each of thelocalized support regions LSR. Contact between the boundary areas CB1,CB2 at the localized support region(s) LSR may be associated withimproved support by the bone model 129 associated with a cortical wallof the load bearing bone. In the implementation of FIG. 9 , the bonemodels 129 may be positioned such that the first boundary area CB1 ofthe first bone model 129-1 may support the second boundary area CB2 ofthe second bone model 129-2 at one or more of the localized supportregions LSR.

Various techniques may be utilized to establish the localized supportregions LSR. The spatial module 137 may be configured to divide thefirst resection surface S1 (and/or second resection surface S2) into twoor more sectors. The sectors may be separate and distinct from eachother. The spatial module 137 may divide the sectors according to equalangles about the axis X. Together the sectors may comprise an entiretyof the respective boundary area CB1/CB2 and/or resection surface S1/S2.In the implementation of FIG. 9 , the spatial module 137 may beconfigured to establish at least four sectors (indicated at I-IV) and atleast four localized support regions LSR (indicated at LSR1-LSR4). Thesectors I-IV may be established at 90 degree increments relative to theaxis X. Each localized support region LSR1-LSR4 may be associated with arespective one of the sectors I-IV. It should be understood that feweror more than four sectors may be established utilizing the techniquesdisclosed herein. A quantity of sectors may be established according tothe selected bone model(s) 129 and/or other aspects of the surgical plan131, including whether or not the surgical plan 131 comprises one ormore implant models 130 to be secured to the selected bone model(s) 129.The spatial module 137 may be configured to establish each localizedsupport region LSR at an outermost position in the respective one of thesectors along the boundary area CB1/CB2 relative to the contact axis X.The localized support region LSR may be equidistant between the innerand outer perimeters PI1/PI2, PO1/PO2. Each localized support region LSRmay be a single point or may be a localized segment along the boundaryarea CB1/CB2. In implementations, each localized support region LSR maybe a region having a length that spans less than or equal to ±10degrees, or more narrowly less than or equal to ±5 degrees, from theoutermost position relative to the contact axis X along the perimeter ofthe boundary area CB1/CB2. A width of the localized support region LSRmay extend between the inner and outer perimeters PI1/PI2, PO1/PO2. Inimplementations, the surgeon or other user may interact with the userinterface 142 to set and/or adjust a position of each localized supportregion LSR. Spacing the localized support regions LSR utilizing thetechniques disclosed herein may promote relatively greater support bythe load bearing bone and improved distribution, may improvedistribution of compressive loads between adjacent bones, and mayimprove fusion between the resection surfaces S1, S2 along the contactregion CR.

The comparison module 138 may be configured to generate one or moreindicators PI in response to one or more predetermined criteria beingmet. The predetermined criteria may include a predefined supportthreshold, which may be associated with a minimum quantity of localizedsupport regions LSR in which contact between the boundary area CB1, CB2is established. The minimum quantity may include at least one, or morethan one, localized support regions LSR. In implementations, the minimumquantity may include two, three or four localized support region LSR.The minimum quantity may include all, or fewer than all, of thelocalized support region LSR established by the spatial module 137.

The indicators PI may include a support indicator PS. The supportindicator PS may include various states, such as an UP arrow indicatingthat the predefined support threshold(s) are not met (e.g., FIG. 10 )and a DOWN arrow indicating that the predefined support threshold(s) arenot met (e.g., FIG. 9 ).

The indicators PI may include graphical indicators PP1-PP4 associatedwith the respective sectors I-IV and localized support regionsLSR1-LSR4. Each of the graphical indicators PP1-PP4 may include ashading or color coding status of the respective portion of the boundaryarea CB1 (e.g., green for contact between the boundary areas CB1, CB2 atthe support region LSR and red for a lack of contact between theboundary areas CB1, CB2 at the support region LSR, shown in hatching inFIGS. 9-10 for illustrative purposes). The comparison module 138 may beconfigured to cause the display module 136 to display the status of thegraphical indicators PP1-PP4 based on whether or not contact isestablished between the boundary areas CB1, CB2 at the respectivelocalized support regions LSR1-LSR4. Each of the indicators PP1-PP4 mayserve as a warning to the surgeon in scenarios in which a lack ofcortical-to-cortical support may exist at the respective localizedsupport regions LSR1-LSR4.

The surgeon, assistant or other user may interact with the menu 146M,directly with the display window 144, and/or with another portion of theuser interface 142 to change a relative position between the first andsecond bone models 129-1, 129-2, as illustrated by FIG. 10 . Inimplementations, the predetermined criteria may include contact betweenthe boundary areas CB1, CB2 for at least two the localized supportregions LSR that are nearest to the implant model 130, as illustrated bythe localized support regions LSR2, LSR3 relative to implant model 130of FIG. 10 . In the implementation of FIG. 10 , the localized supportregions LSR1-LSR3 may correspond to contact between the boundary areasCB1, CB2 associated with the medial, lateral and anterior regions of theload bearing bone (e.g., talus) and the supported bone (e.g., tibia).

Referring to FIG. 11 , with continuing reference to FIGS. 2 and 6 , thepredetermined criteria may include a length ratio associated with ashortening of the respective bone model 129 relative to the specifiedresection plane REF (see also FIG. 4 ). The spatial module 137 may beconfigured to determine a first distance D1 along a longitudinal axis LAbetween a first end 129A and a second end 129B of the bone model 129,such as the second bone model 129-2. The spatial module 137 may beconfigured to determine a second distance D2 along the longitudinal axisLA between the specified reference plane REF and the second end 129B ofthe bone model 129.

The comparison module 138 may be configured to determine a length ratioD2:D1 in response to setting a position of the reference plane REF. Thelength ratio D2:D1 may be defined as a ratio of the second distance D2divided by the first distance D1. The comparison module 138 may beconfigured to generate a length indicator PIL in response to the lengthratio D2:D1 being less than (or greater than) a predefined lengththreshold. The indicator PIL may include various states relating to theresection depths, such as an UP arrow indicating that the predefinedlength threshold is met (e.g., FIGS. 5-6 ) and a DOWN arrow indicatingthat the predefined length threshold is not met (e.g., FIG. 8 ). Inimplementations, the predefined length threshold may be less than orequal to 0.05, or more narrowly less than or equal to 0.01. Theindicator PIL may serve to provide an indication to the surgeon whetherto increase or decrease a depth of the resection plane REF associatedwith the bone model 129, which may reduce limb shortening and improvehealing and mobility of the patient.

Referring to FIGS. 12-13 , with continuing reference to FIG. 2 , thedisplay module 136 may be configured to display one or more implantmodels 130 in one or more of the display window(s) 144 of the userinterface 142 (see also FIGS. 9-10 ). Each implant model 130 can beassociated with any of the implants disclosed herein. The displaywindows 144 may include eighth through tenth display windows 144-8 to144-10 (FIG. 12 ) and eleventh through thirteen display windows 144-11to 144-13 (FIG. 13 ). The spatial module 137 may be configured toposition the implant model(s) 130 relative to the first and second bonemodels 129-1′, 129-2′ automatically and/or in response to userinteraction with the user interface 142.

The system 120 may be configured to facilitate positioning of theselected implant model(s) 130 relative to the bone models 129-1′,129-2′. For example, the surgeon may desire to place the implant model130 relatively closer to the bone models 129-1′, 129-2′ than would bepermitted by an existing surface contour of the bone models 129-1′,129-2′ due to a spatial conflict. The surgeon or assistant may interactwith the user interface 142 to cause at least a portion of the volume ofthe selected implant model 130 to overlap with a volume of therespective bone models 129-1′, 129-2′ resulting in a spatial conflict.

The spatial module 137 may be configured to determine one or moreoverlapping volumes between the implant model 130 and the first andsecond bone models 129-1′, 129-2′ associated with the overlappedpositioning. The display module 136 may be configured to display avisual contrast between the one or more overlapping volumes and aremainder of the volumes of the first and second bone models 129-1′,129-2′ that excludes the one or more overlapping volumes. Inimplementations, the visual contrast may be established by one or morevisual indicators VI applied to the overlapping volumes (shown inhatching for illustrative purposes). The visual contrast may serve as aheat map to emphasize areas of spatial conflict, which the surgeon mayutilize to evaluate whether planned implant repositioning and/or removalof bone with one or more relief cuts is indicated prior to approving thesurgical plan 131. The relief cuts may be simulated by partially orsubstantially removing the overlapping volumes from display in the userinterface 142. One of ordinary skill in the art would understand how toprogram the spatial module 137 with logic to determine the overlappingvolumes, including one or more CAD tools, libraries, etc.

The spatial module 137 may be configured to generate an iteration of thefirst and second bone models 129-1″, 129-2″. The bone models 129-1″,129-2″ may exclude the one or more overlapping volumes, as illustratedby display window 144-13 with overlapping volumes V1, V2 shown in dashedlines and implant model 130 for illustrative purposes. The displaymodule 136 may be configured to display the implant model(s) 130positioned relative to the bone models 129-1″, 129-2″, as illustrated bydisplay window 144-13. The bone models 129-1″, 129-2″ may be separatemodels or may be stored as one or more revisions to the respective bonemodels 129-1/129-1′, 129-2/129-2′.

Referring to FIGS. 14-15 , with continuing reference to FIGS. 2 and 6 ,the spatial module 137 may be configured to determine one or moretrajectories T for placement of respective guide members. Exemplaryguide members may include guide pins (e.g., Kirschner wires), fasteners,etc. The trajectories T may include first through fourth trajectoriesT1-T4. Each trajectory T may include a location of insertion along asurface of the bone model 129-1′/129-2′ and/or orientation along an axispassing through the location. The trajectories T may be associated withrespective guide pins configured for insertion into bone (see, e.g.,FIGS. 27 and 36 ). The spatial module 137 may be configured to determinethe trajectories T in response to one or more (or each) of thepredetermined criteria being met, including any of the predeterminedcriteria disclosed herein, such as one or more (or each) of thepredefined thresholds being met. The predefined thresholds may beassociated with the determined contact area ratio CAR and/or relatedparameters, such as the determined cancellous coverage ratio CCR anddetermined cortical coverage ratio COR. The predefined threshold(s) maybe associated with the determined cortical support ratio CSR. Inimplementations, the surgeon may interact with the user interface 142 toapprove the defined reference planes REF associated with the resectionsurfaces S1, S2.

The trajectories T1-T4 may be associated with respective positions alongthe bone models 129-1′, 129-2′ relative to the contact region CR (FIG.14 ). The spatial module 137 may be configured to establish thetrajectories T1-T4 based on one or more landmarks L, such as thelandmarks L1, L2, and/or the defined reference planes REF (see also FIG.4 ). The surgeon or assistant may interact with the user interface 142to adjust a position and/or orientation of each trajectory T.

The comparison module 138 may be configured to generate one or moresettings or dimensions associated with an instrument based on thetrajectories T. Exemplary instruments may include cutting blocks,trajectory guides, etc., including any of the instruments disclosedherein. The dimensions may be utilized to fabricate a patient-specificinstrument for implementation of the surgical plan 131. The trajectoriesT, settings and/or dimensions may be stored in the surgical plan 131.The surgeon may interact with the user interface 142 to approve thesurgical plan 131, which may be stored in the database 128 for laterretrieval.

FIG. 17 illustrates an exemplary trajectory assembly 250 that may beutilized for various surgical procedures, including preparation of asurgical site. The trajectory assembly 250 may be configured to positionone or more guide members relative to bone or other tissue based on oneor more predetermined trajectories. The trajectory assembly 250 may beutilized in an ankle reconstruction to facilitate the removal of bonealong an articulating surface of a tibia and/or talus. A location of thebone to be removed may be determined during preoperative planningutilizing the system 120.

The assembly 250 may include a trajectory guide 252 and a secondaryguide 254. The secondary guide 254 may be releasably secured orotherwise coupled to the trajectory guide 252. In other implementations,the secondary guide 254 may be integrally formed with the trajectoryguide 252. The trajectory guide 252 and secondary guide 254 may beutilized in the positioning of one or more guide members relative toeach other and bone or other tissue at a surgical site.

The trajectory guide 252 may include an elongated guide body 256 and atleast one or more arm members 258 coupled to the guide body 256. Theguide body 256 may extend along a longitudinal axis GA between a first(e.g., proximal) end portion 256A and a second (e.g., distal) endportion 256B. The guide body 256 may be configured to set a trajectoryof one or more guide member relative to tissue such as bone. The guidebody 256 may include a guide passage 260 extending along a passage axisPX. The passage axis PA may be substantially collinear with or parallelto the longitudinal axis GA. The guide passage 260 may be dimensioned toreceive a guide member, such as a guide pin GP. The guide pin GP may bepositioned at a predetermined trajectory relative to bone along asurgical site. The arm members 258 may be configured to set anorientation of the longitudinal axis GA of the guide body 256 relativeto bone along the surgical site and establish a trajectory of the guidepin GP insertable through the guide passage 260 relative to the bone orother tissue.

The trajectory guide 252 may include an array of arm members 258distributed about a periphery and longitudinal axis GA of the guide body256. Each of the arm members 258 may be integrally formed with orattached to the guide body 256 at a fixed position, or may be moveablerelative to each other and/or the guide body 256. The arm members 258may extend laterally from the guide body 256. Although the trajectoryguide 252 is illustrated having a total of five arm members 258, itshould be understood that fewer or more than five arm members 258 may beutilized in accordance with the teachings disclosed herein, such as onlyone arm member 258.

Each of the arm members 258 may be movable in a first (e.g., axial)direction DM relative to the guide body 256 to set a trajectory of theguide member relative to tissue such as bone. The direction DM may besubstantially parallel to the longitudinal axis GA and/or passage axisPX. Each of the arm members 258 may be independently movable in thedirection DM and trajectory of the guide member(s) relative to tissuesuch as bone. The arm members 258 may be configured relative to indiciaI. The indicia I may be associated with respective positions relative tothe longitudinal axis GA. The surgeon or assistant may move the armmembers 258 relative to the indicia I according to one or more settingsspecified in a surgical plan 131 generated by the system 120 (FIG. 2 ).The arm members 258 may set the trajectory in response to abutment witha contact surface along the bone. Each of the arm members 258 mayinclude various geometries and configurations to establish a trajectoryof the longitudinal axis GA of the guide body 256 and associated guidemember(s) relative to the surgical site. In implementations, the armmembers 258 may be dimensioned to establish a single point of contact, astaircasing arrangement including two or more points of contact (see,e.g., FIG. 17 ), a wrapping arrangement including two or more points ofcontact established by overhanging arm members (see, e.g., FIG. 17 ),and hooking (e.g., C-shaped) overhanging arm members.

Referring to FIGS. 17-18 , the secondary guide 254 may include a mainbody 262 extending along a guide (e.g., longitudinal) axis GS. The guideaxis GS may be substantially collinear with or otherwise parallel to thelongitudinal position GA of the trajectory guide 252 in an installedposition.

The main body 262 may include a sleeve portion 266 and a flange portion268 extending outwardly from a perimeter of the sleeve portion 266. Thesecondary guide 254 may be carried by the guide body 256 in theinstalled position. The sleeve portion 266 may have a generally annularor hoop-shaped geometry dimensioned to mate with the outer periphery ofthe guide body 256. The sleeve portion 266 may have a sleeve passage 267dimensioned to at least partially receive a proximal end portion 256A ofthe guide body 256.

The trajectory guide 252 may include an abutment 256F along the outerperiphery of the guide body 256 (FIG. 17 ). The abutment 256F may be anannular flange extending outwardly from the guide body 256. The abutment256F may serve as an axial stop to limit axial movement of the secondaryguide 254 relative to the longitudinal axis GA of the guide body 256.The secondary guide 254 may be translatable along the passage axis PXand/or longitudinal axis GA to engage the abutment 256F such thatrelative movement between the secondary guide 254 and guide body 256 islimited relative to the axes PX and/or GA.

The main body 262 may include at least one or more apertures 264. Eachaperture 264 may be established with respect to a predefined positionrelative to the guide axis GS of the secondary guide 254. At least oneof the apertures 264 may be established along the flange portion 268.The apertures 264 may be established at different pitches relative tothe guide axis GS. The apertures 264 may be arranged in one or more rowsdistributed about the guide axis GS, as illustrated by first and secondrows 264-1, 264-2 along the flange portion 268. The second row 264-2 ofapertures 264 may be outward of the first row 264-1 of aperturesrelative to the guide axis GS. Two or more apertures 264 of adjacentrows 264-1, 264-2 may be substantially circumferential aligned withrespect to the guide axis GS, but may be associated with differentoffsets or distances from the guide axis GS to position guide pins GP atdifferent distances from each other. Each aperture 264 of the first row264-1 of apertures 264 may be substantially circumferentially alignedwith a respective aperture 264 of the second row 264-2 of apertures 264relative to the guide axis GA. The apertures 264 may be spaced apart inapproximately 1 degree increments relative to the guide axis GA.

Each aperture 264 may be dimensioned to at least partially receive arespective guide pin GP along a respective aperture axis AA. Thesecondary guide 254 may be coupled to the guide body 256 such that eachaperture axis AA is offset from the passage axis PX, longitudinal axisGA and/or guide axis GS by a predetermined distance and predeterminedcircumferential position. Each aperture axis AA may be substantiallyparallel to the axes PX, GA and/or GS. The selected aperture(s) 364 maybe specified in the surgical plan 131 (FIG. 2 ).

The secondary guide 254 may be arranged at different orientationsrelative to the trajectory guide 252. The assembly 250 may include oneor more features to set the relative orientation between the trajectoryguide 252 and secondary guide 254 along an interface 270 in an installedposition. Referring to FIG. 18 , with continuing reference to FIG. 17 ,the trajectory guide 252 may include a first interface feature 271 alongthe guide body 256. The secondary guide 254 may include a secondinterface feature 272 along the sleeve portion 266. The first interfacefeature 271 may be dimensioned to engage with the second interfacefeature 272 at the interface 270 to set the position of the secondaryguide 254 and limit relative rotation between the guide body 256 andsecondary guide 254 with respect to the longitudinal axis GA. The firstinterface feature 271 may be utilized to vary and set the positions ofthe apertures 264 relative to the guide axis GS, which may provide thesurgeon or assistant improved versality in selecting desiredtrajectories of the guide pins GP.

The first interface feature 271 may be a protrusion extending outwardlyfrom the outer periphery of the guide body 256, and he second interfacefeature 272 may include at least one groove along the sleeve passage 267dimensioned to mate with the protrusion 271, although an oppositearrangement may be utilized. The second interface feature 272 mayinclude an array of the grooves distributed along the sleeve passage267. The protrusion 271 may be insertable within a selected one of thegrooves 272 to set a circumferential position of the apertures 264relative to the axes PX and/or GA of the guide body 256 and to limitrelative rotation between the guide body 256 and secondary guide 254.

The trajectory guide 252 may be utilized with one or more secondaryguides, such as a secondary guide 354 (FIG. 19 ) and/or secondary guide454 (FIGS. 34-35 ). Referring to FIG. 19 , the secondary guide 354 mayinclude a sleeve portion 366 and a flange portion 368. The flangeportion 368 may establish first and second rows 364-1, 364-2 ofapertures 364. The flange portion 368 may include a first section 368Aand a second section 368B that establish a stepped arrangement. Thefirst row 364-1 of apertures 364 may be established along the firstsection 368A. The second row 364-2 of apertures 364 may be establishedalong the second section 368B. The first and second rows 364-1, 364-2may be utilized to position guide pins in respective bones. For example,the second row 364-2 may be utilized to position a guide pin in a longbone such as a talus, and the first row 364-1 may be utilized toposition a guide pin in an adjacent bone, such as a talus.

FIGS. 20-21 illustrates an exemplary method of planning and performingan orthopaedic procedure in a flowchart 274. The method 274 may beutilized to pre-operatively plan and perform an arthroplasty forrestoring functionality to ankles, shoulders, knees, hips and otherjoints having advanced cartilage disease, for example. The method 274may be utilized with any of the instrumentation and orthopedic implantsdisclosed herein, including the trajectory assembly 250 and secondaryguides 254, 354. The method 274 may be utilized to determine whethersufficient contact area may be established between resected bonesurfaces to promote fusion of adjacent bones, and may be utilized toconfigure one or more instruments for performing an orthopaedicprocedure according to an associated surgical plan for a patient. Feweror additional steps than are recited below could be performed within thescope of this disclosure, and the recited order of steps is not intendedto limit this disclosure. Reference is made to the system 120 and userinterface 142 for illustrative purposes.

Referring to FIGS. 2-3 , with continuing reference to FIG. 20 , at step274-1 a first bone model 129-1 and a second bone model 129-2 may beselected from a plurality of bone models 129. The models 129-1, 129-2may be selected in response to user interaction with the menu 146Massociated with the first display window 144-1 or another portion of theuser interface 142. The second bone model 129-2 may be associated with along bone such as a tibia. The first bone model 129-1 may be associatedwith an adjacent bone, such as a talus or an adjacent long bone.

At step 274-2, the first and second bone models 129-1, 129-2 may bedisplayed in the graphical user interface 142 such that a firstarticular surface AS1 of the first bone model 129-1 opposes and contactsa second articular surface AS2 of the second bone model 129-2, asillustrated in the first display window 144-1. The bone models 129-1,129-2 may be displayed in the user interface 142 such that the firstarticular surface AS1 opposes, but is spaced apart from, the secondarticular surface AS2, as illustrated in the second display window144-2.

At step 274-3, one or more landmarks L may be set or otherwiseindicated, as illustrated in the second display window 144-2. Thelandmarks L may be set automatically by the system 120 and/or inresponse to user interaction with the menu 146M associated with thesecond display window 144-2, direct interaction with the second displaywindow 144-2 and/or another portion of the user interface 142.

Referring to FIG. 4 , with continuing reference to FIG. 20 , at step274-4 one or more reference planes REF may be set or otherwise indicatedrelative to the bone models 129-1, 129-2. Step 274-4 may include settingor otherwise indicating a (e.g., first) reference plane REF (e.g.,REFS-REFS) in the user interface 142 to establish the first resectionsurface S1 of the first bone model 129-1. Step 274-4 may include settingor otherwise indicating a (e.g., second) reference plane REF (e.g.,REF1-REF4) in the user interface 142 to establish the second resectionsurface S2 of the second bone model 129-2. The reference planes REF maybe set in response to user interaction with the menu 146M associatedwith the third display window 144-3, direct interaction with the thirddisplay window 144-3 and/or another portion of the user interface 142.The user may specify an offset distance or resection depth utilizing theentry field 146E.

At step 274-5, one or more of the bone models 129-1, 129-2 may bemodified. The modification may be applied to a local copy of the bonemodels 129-1, 129-2 and/or a global copy of the bone models 129-1, 129-2in the database 128. Step 274-5 may include generating at least one(e.g., first) iteration of first and second (e.g., resection) bonemodels 129-1′, 129-2′ at step 274-6. The bone models 129-1′, 129-2′ mayexclude respective volumes of the bone models 129-1, 129-2 between thereference planes REF and articular surfaces AS1, AS2 of the bone models129-1, 129-2, as illustrated in the fourth display window 144-4.

At step 274-7, the first resection surface S1 of the first bone model129-1′ may be positioned in contact with the second resection surface S2of the second bone model 129-2′ to establish a contact region CR. Atstep 274-8, at least portions of the bone models 129-1′, 129-2′ alongthe contact region CR may be displayed in the graphical user interface142.

The method 274 may determine various characteristics associated with thecontact region CR. In implementations, the method 274 may be utilized todetermine whether or not sufficient contact area along the contactregion CR may be established between resected bone surfaces S1, S2 topromote fusion of adjacent bones associated with the bone models 129-1′,129-2′.

At step 274-9, one or more parameters associated with the contact regionCR and resection surfaces S1, S2 may be determined. The parameters mayinclude any of the disclosed parameters and may be determined utilizingany of the techniques disclosed herein. In implementations, step 274-9may include determining a contact area ratio CAR at step 274-9A,determining a cortical coverage ratio COR at step 274-9B, determining acortical support ratio CSR at step 274-9C, determining a cancellouscoverage ratio CCR at step 274-9D, and/or determining a length ratioD2:D1 at step 274-9E. Steps 274-9A to 274-9E may be performed utilizingany of the techniques disclosed herein.

Referring to FIGS. 5-6 , with continuing reference to FIG. 20 , thecontact area ratio CAR, cortical coverage ratio COR and/or cancellouscoverage ratio CCR may be associated with the first and second resectionsurfaces S1, S2 along the contact region CR. The length ratio D2:D1 maybe associated with one of the bone models, such as the second bone model129-2, as illustrated in FIG. 11 .

Determining the contact area ratio CAR at step 274-9A may includedetermining a first area A1 of the first resection surface S1 along thecontact region CR and determining a second area A2 of the secondresection surface S2.

Determining the cortical coverage ratio COR at step 274-9B may includedetermining a first cortical area CO1 along the first resection surfaceS1. The first cortical area CO1 may be associated with cortical bone.Step 274-9B may include determining a second cortical area CO2 along thesecond resection surface S2. The second cortical area CO2 may beassociated with cortical bone. The first cortical area CO1 may be lessthan, or may otherwise differ from, the second cortical area CO2. Step274-9B may include determining an area of overlap between the first andsecond cortical areas CO1, CO2 along the contact region CR.

Determining the cortical support ratio CSR at step 274-9D may includedetermining a cortical area CO1/CO2 and a respective boundary areaCB1/CB2. Step 274-9D may include determining a cortical support ratioCSR for the first bone model 129-1 and/or the second bone model 129-2.The cortical support ratio CSR may be associated withcortical-to-cortical bone contact.

Determining the cancellous coverage ratio CCR at step 274-9D may includedetermining a first cancellous area CA1 along the first resectionsurface S1. The first cancellous area CA1 may be associated withcancellous bone. Step 274-9C may include determining a second cancellousarea CA2 along the second resection surface S2. The second cancellousarea CA2 may be associated with cancellous bone. The first cancellousarea CA1 may be less than, or may otherwise differ from, the secondcancellous area CA2. Step 274-9C may include determining an area ofoverlap between the first and second cancellous areas CAL CA2 along thecontact region CR.

Referring to FIG. 11 , with continuing reference to FIG. 20 ,determining the length ratio D2:D1 at step 274-9E can includedetermining a first distance D1 along a longitudinal axis LA between afirst end 129A and a second end 129B of a bone model 129, such as thesecond bone model 129-2. Step 274-9E can include determining a seconddistance D2 along the longitudinal axis LA between the a (e.g., second)reference plane REF and the second end 129B of the bone model 129, suchas the second bone model 129-2.

At step 274-10, the method 274 may include determining whether or notone or more predetermined criteria are met and/or are not met. Thepredetermined criteria can include any of the predetermined criteriadisclosed herein. Determining whether or not the predetermined criteriaare met or are not met may be determined utilizing any of the techniquesdisclosed herein, including comparing values of the contact area ratioCAR, cortical coverage ratio COR, cortical support ratio CSR, cancellouscoverage ratio CCR and/or length ratio D2:D1 to one or more predefinedthresholds. The predefined thresholds can include any of the predefinedthresholds disclosed herein. Each predefined threshold may be set basedon patient characteristics such as height and limb length and may bespecified in the surgical plan 131.

The predetermined criteria can include the contact area ratio CARmeeting a predefined threshold. In implementations, the predeterminedcriteria can include the contact area ratio CAR being greater than orequal to a first predefined threshold. The first predefined thresholdmay include any of the values disclosed herein. The first predefinedthreshold may be greater than or equal to 0.4, more narrowly greaterthan or equal to 0.5. The first predefined threshold may be greater thanor equal to 0.75, or more narrowly equal to 1.0.

The predetermined criterion can include the cortical coverage ratio CORmeeting a predefined threshold. In implementations, the predeterminedcriteria can include the cortical coverage ratio COR being greater thanor equal a second predefined threshold. The second predefined thresholdmay include any of the values disclosed herein. The second predefinedthreshold may be greater than or equal to 0.03, or more narrowly greaterthan or equal to 0.05.

The predetermined criteria can include the cancellous coverage ratio CCRmeeting a predefined threshold. In implementations, the predeterminedcriteria can include the cancellous coverage ratio CCR being greaterthan or equal to a third predefined threshold. The third predefinedthreshold may include any of the values disclosed herein. The thirdpredefined threshold may be greater than or equal to 0.75, more narrowlygreater than or equal to 0.90, or even more equal to 1.0.

The predetermined criteria can include the length ratio D2:D1 meeting a(e.g., fourth) predefined (e.g., length) threshold. The fourthpredefined threshold may include any of the values disclosed herein. Inimplementations, the fourth predefined threshold may be less than orequal to 0.05, or more narrowly less than or equal to 0.01.

The predetermined criteria can include the contact to resection ratioCRR meeting a fifth predefined threshold. The fifth predefined thresholdmay include any of the values disclosed herein. In implementations, thefifth predefined threshold may include a contact to resection ratio CRRgreater than or equal to 0.75, more narrowly greater than or equal to0.90, or even more narrowly equal to 1.0.

The predetermined criteria can include the cortical support ratio CSRmeeting a sixth predefined threshold. The sixth predefined threshold mayinclude any of the values disclosed herein. In implementations, thesixth predefined threshold may include a cortical support ratio CSRgreater than or equal to 0.50, more narrowly greater than or equal to0.75, more narrowly greater than or equal to 0.90, or even more narrowlyequal to 1.0.

At steps 274-11 and 274-12, the method 274 may include generating anddisplaying at least one or more indicator PI in the user interface 142in response to one or more predetermined criteria being met and/or notmet. The status of each indicator PI may be individually set and/orupdated. Step 274-11 may include generating one or more indicators PI inresponse to one or more predetermined criteria being met and/or not met.In implementations, a status of the indicator PI may be set based onwhether or not the respective predetermined criteria are met or are notmet. Step 274-12 may include displaying at least one or more indicatorsPI in the user interface 142 associated with the contact area ratio CARin response to one or more of the predetermined criteria being met.

The indicators PI can include a value of the contact area ratio CARdetermined at step 274-9A, a value of the cortical coverage ratio CORdetermined at step 274-9B, and/or a value of the cancellous coverageratio CCR determined at step 274-9D, as illustrated by the graphic 146Gof FIG. 5 . The indicators PI can include a value of the corticalsupport ratio CSR determined at step 274-9C, as illustrated by theindicator PVC of FIG. 6 . The indicators PI can include a value of thelength ratio D2:D1 determined at step 274-9E, as illustrated byindicator PVL in FIGS. 5-6 and 8 .

Step 274-12 may include displaying a visual contrast between the contactregion CR and a remainder of the first and second resection surfaces S1,S2 that excludes the contact region CR at step 274-12A, as illustratedby respective graphics R1, R2 in FIG. 7 . Step 274-12A may includedisplaying a visual contrast between portions of the contact region CRassociated with cortical bone and cancellous bone, illustrated byrespective graphics R1A, R1B in FIG. 7 .

Step 274-12 may include displaying one or more indicators PI associatedwith the localized support regions LSR at step 274-12C, such as thesupport indicators PP1-PP4 of FIGS. 9-10 . The support indicatorsPP1-PP4 may be associated with respective localized support regionsLSR1-LSR4.

Referring to FIG. 8 , with continuing reference to FIG. 20 , determiningthe contact area ratio CAR at step 274-9A may include determining a setof values of the contact area ratio CAR associated with differentpositions of the first resection surface S1 relative to the secondresection surface S2 along the contact region CR, with values in the setof values of the contact area ratio CAR corresponding to respectivedirections along the contact region CR. Each value may be associatedwith a respective vector or coordinate along the resection surface S1/S2such that values may be determined for substantially all relativepositions between the bone models 129-1′, 129-2′ in which contactbetween the resection surfaces S1, S2 is maintained. Step 274-9A mayinclude determining a maximum value of the set of values of the contactarea ratio CAR in which contact is maintained between the resectionsurfaces S1, S2.

Step 274-12 may include displaying one or more directional indicators DAat step 274-12B, as illustrated in the seventh display window 144-7. Thedirectional indicators DA may be associated with the respective valuesof the contact area ratio CAR determined at step 274-9A. The directionalindicators DA may include a (e.g., first) directional indicator DA-1associated with a maximum value of the set of values of the contact arearatio CAR determined at step 274-9A. Step 274-12B may include displayingthe directional indicator DA-1 relative to the contact region CR.

At step 274-13, the first and second bone models 129-1′, 129-2′ may bemoved relative to each other based on the one or more indicators PI.Step 274-12 may include moving the first bone model 129-1′ in a seconddirection DIR2 relative to the first bone model 129-2′ along the contactregion CR. The second direction DIR2 may be substantially aligned with adirection corresponding to the first directional indicator DA-1. Step274-13 may include moving the first and second bone models 129-1, 129-2relative to each other to increase or otherwise vary the corticalsupport ratio CSR and/or quantity of localized support regions LSR inwhich contact is established between the cortical boundary areas CB1,CB2, as illustrated by FIGS. 9-10 . Determining one or more parametersassociated with the resection surfaces S1, S2 and contact region CR maybe repeated or updated at step 274-9, including steps 274-9A, 274-9B,274-9C, 274-9D and/or 274-9E, in response to relative movement betweenthe bone models 129-1′, 129-2′ at step 274-13.

Referring to FIGS. 2 and 12 , with continuing reference to FIG. 20 , atstep 274-14 one or more implant models 130 may be selected from aplurality of implant models 130. The implant model(s) 130 may beselected automatically based on various attributes of the patientincluding the selected bone models 129 and/or in response to userinteraction with the menu 146M adjacent to the display windows 144-8 to144-10 and/or another portion of the user interface 142. The implantmodels 130 can include any of the implants disclosed herein.

At step 274-15, the selected implant model(s) 130 may be positionedrelative to the first and/or second bone models 129-1′, 129-2′, whichmay occur subsequent to establishing the contact region CR at step274-7. The selected implant model(s) 130 may be displayed in the userinterface 142. One or more iterations of moving the bone models 129-1′,129-2′ relative to each other at step 274-13 may occur prior to, duringand/or subsequent to positioning the implant model(s) 130 at step274-15.

The method 274 may determine a relative fit between the selected implantmodel(s) 130 and the bone models 129-1′, 129-2′ at the specifiedposition. At step 274-16, one or more overlapping volumes between theselected implant model(s) 130 and the bone models 129-1′, 129-2′ may bedetermined. The overlapping volumes may be determined utilizing any ofthe techniques disclosed herein. Step 274-16 may include moving theselected implant model(s) 130 relative to the bone models 129-1′,129-2′, and then repeating the determination of any overlapping volumesfor the respective position.

At step 274-12A, one or more indicators may be displayed based on theoverlapping volumes together with the selected implant model(s) 130.Step 274-12A may include displaying a visual contrast between theoverlapping volume(s) and a remainder of the volumes of the bone models129-1′, 129-2′ that excludes the overlapping volume(s). Inimplementations, the visual contrast may be established by one or morevisual indicators VI applied to the overlapping volumes (shown inhatching in FIGS. 12-13 for illustrative purposes).

Referring to FIG. 13 , with continuing reference to FIGS. 12 and 20 ,one or more of the bone models 129-1′, 129-2′ may be modified at step274-17. Step 274-17 may include generating an (e.g., second) iterationof the first and/or second bone models 129-1″, 129-2″ that excludes theoverlapping volumes at step 274-17A.

The method 274 may include repeating step 274-16 to determine anyoverlapping volumes for each iteration of the first and/or second bonemodels 129-1″, 129-2″ relative to the selected implant(s) 130. Themethod 274 may include repeating step 274-15 to move and/or display theselected implant model(s) 130 for each subsequent iteration of the firstand second bone models 129-1″, 129-2″. Repeating step 274-15 may includeadjusting a position of the selected implant(s) 130 in response to userinteraction with the menu 146M, directly with one of the display windows144-8 to 144-12, and/or another portion of the user interface 142. Step274-17 may be repeated until any overlapping volumes are eliminated orotherwise reduced. Utilizing the techniques disclosed herein, arelatively close fit can be established between the selected implant(s)130 and adjacent surfaces of the bone models 129-1″, 129-2″, which canimprove healing of the patient.

At step 274-18, the surgeon or another user can approve a surgical plan131 (FIG. 2 ). The surgical plan 131 can include any of the parametersestablished in the method 274, including the landmarks L associated withthe bone models 129-1, 129-2, the bone models 129-1/129-1′/129-1″,129-2/129-2′/129-2″, the specified resection planes REF associated withthe resection surfaces S1, S2, selected implant model(s) 130, and/oroverlapping volumes that may indicate relief cut(s) to accommodate animplant.

Referring to FIG. 21 , with continuing reference to FIG. 20 , the method274 may include one or more steps to implement each surgical plan 131.Referring to FIGS. 14-15 , with continuing reference to FIG. 21 , themethod 274 may include determining one or more trajectories T associatedwith surgical device(s) at step 274-19, including any of the guidemembers disclosed herein such as a guide pin. The trajectories T may beassociated with positions along the respective bone model 129-1′, 129-2′relative to the contact region CR, which may be subsequently establishedby one or more resections. Step 274-19 may include determining a firsttrajectory T1 associated with a first guide pin GP-1 and a secondtrajectory T2 associated with a second guide pin GP-2 (see, e.g., FIG.27 ). Step 274-19 may include determining a third trajectory T3associated with a third guide pin GP-3 and a fourth trajectory T4associated with a fourth guide pin GP-4 (see, e.g., FIG. 36 ). The firstand second trajectories T1, T2 may be associated with respective firstand second positions along one of the bone models 129-1′, 129-2′relative to the contact region CR (FIG. 14 ), such as the first bonemodel 129-1′. The third and fourth trajectories T3, T4 may be associatedwith respective third and fourth positions along another one of thefirst and second bone models 129-1′, 129-2′ relative to the contactregion CR (FIG. 14 ), such as the second bone model 129-2′.

Step 274-19 may occur in response to the contact area ratio CAR meetingone or more predefined thresholds and/or other predetermined criteria,including any of the predetermined criteria and thresholds disclosedherein. The positions of the trajectories T1/T3, T2/T4 may beestablished along a common one of the bone models 129-1/129-1′,129-2/129-2′ adjacent the resection surface S1/S2. Although pairs of thetrajectories T1/T3, T2/T4 are disclosed, it should be understood thatthe techniques disclosed herein can be utilized to establish a singletrajectory or more than two trajectories associated with each bone model129-1/129-1′, 129-2/129-2′.

One or more settings and/or dimensions for surgical instrument(s) may begenerated at step 274-20. The setting(s) and dimension(s) may beassociated with a trajectory assembly and/or another surgical instrumentbased on the trajectories T1, T2, T3 and/or T4 associated with at leastone, or each, of the bone models 129-1/129-, 129-2/129-2′. Thetrajectory assemblies can include any of the trajectory assembliesdisclosed herein, such as the trajectory assembly 250. The settingsgenerated at step 274-20 can be stored in a surgical plan 131 (FIG. 2 ).Exemplary settings include patient information, procedure type, implanttype and position, fastener sizes and lengths, resection depths andangles, targeting guide and secondary guide positions, secondary guideaperture selections, arm member lengths and positions relative to thesurgical site, relief cut locations and depths, guide membertrajectories and insertion points, etc.

At step 274-21, one or more surgical instruments can be configuredaccording to the setting(s) and dimension(s) generated at step 274-20.Step 274-21 may include configuring the surgical instrument(s) accordingto any of the techniques disclosed herein. Step 274-21 may includefabricating surgical instrument(s) at step 274-21A according to thedimension(s) generated at step 274-20. The fabricated instrument(s) mayinclude one or more patient-specific surfaces or components.

Referring to FIG. 22 , with continuing reference to FIGS. 21 , step274-21 may include moving component(s) of the instrument(s) at step274-21B according to the setting(s) generated at step 274-20. Theinstrument may include a trajectory assembly 350. The trajectoryassembly 350 may include a trajectory guide 352 and a secondary guide354 coupled to the trajectory guide 352.

Step 274-21 may include configuring the trajectory guide 352 and/orsecondary guide 354 (FIG. 25 ) according to the setting(s) to establishthe predetermined trajectories T. The third and fourth trajectories T3,T4 in FIGS. 22-24 may correspond to the trajectories T3, T4 of FIGS.14-15 , and the first and second trajectories T1, T2 in FIGS. 25-27 maycorrespond to the trajectories T1, T2 of FIGS. 14 and 16 .

The trajectory assembly 350, including the secondary guide 354 andsecondary guide 354, may be configured utilizing any of the techniquesdisclosed herein. Step 274-21B may include moving one or more of armmembers 358 from a first position to a second position relative to aguide body 356 of the trajectory guide 352 to establish the trajectoryT3, which may be established along the passage axis PX. Step 274-21B mayinclude moving the arm members 358 relative to the guide body 356 torespective positions according to the setting(s). The arm members 358may be moved in a direction DM relative to a longitudinal axis GA of theguide body 356.

At step 274-22, the instrument(s) may be moved into abutment with one ormore bones 376 at the surgical site S. The bones 376 can include a firstbone 376-1 and a second bone 376-2 that cooperate to establish a joint375. The second bone 376-2 may be a long bone such as a tibia. The firstbone 376-1 may be an adjacent bone such as a talus. The first and secondbones 376-1, 376-2 may be associated with respective ones of theselected bone models 129-1, 129-2 (FIG. 3 ).

Step 274-22 may include moving the trajectory guide 352 in a directionDT3 and into abutment with one of the bones 376 to set the trajectory T3of the guide pin GP-3 relative to tissue including one of the bones 376such as the bone 376-2. Step 274-22 may occur such that surfaces of thearm members 358 abut predetermined positions of the bone 376-2 accordingto the setting(s) and associated surgical plan 131 (FIG. 2 ), asillustrated in FIGS. 22-24 .

At step 274-23, one or more guide members may be positioned with thetrajectory assembly 350, such as one or more guide pins GP. Theinstruments including the trajectory assembly 350 (and assembly 450, seeFIG. 32 ) may be configured such that the corresponding guide pin GPtrajectories and insertion points are established relative to the bones376 to ensure resections substantially conform to the surgical plan 131,including specified resection depths and positions.

Step 274-23 may include positioning the guide pin GP-3 through the guidepassage 360 and then into the bone 376-2 with the trajectory guide 352according to the associated (e.g., third) trajectory T3 (see, e.g.,FIGS. 14-15 ) specified by one or more parameters in the surgical plan131. The third guide pin GP-3 may be moved in a direction DP3 such thatthe guide pin GP-3 is at least partially received in and through theguide passage 360 of the guide body 356 along the passage axis PX toestablish the trajectory T3.

The secondary guide 354 may be moveable relative to the longitudinalaxis GA of the trajectory guide 352. The secondary guide 354 may bepositioned prior to, during and/or subsequent to positioning thetrajectory guide 352 at a surgical site S. Step 274-21 may includemoving a secondary guide 354 relative to the guide body 356 of thetrajectory guide 352 according to the setting(s). Step 274-21 mayinclude setting a position of the secondary guide 354 relative to thelongitudinal axis GA to establish the fourth trajectory T4 relative tothe third trajectory T3.

Step 274-21 may include moving the secondary guide 354 in a directionRD1 (FIG. 26 ) about the longitudinal axis GA of the guide body 356according to the setting(s). A main body 362 of the secondary guide 354may be rotated or otherwise moved relative to the longitudinal axis GAsuch that aperture(s) 364 move from a first circumferential position toa second circumferential position relative to the longitudinal axis GA.A relative orientation or position of the trajectory guide 352 andsecondary guide 354 may be set in response to engagement between firstand second interface features 371, 372 at an interface 370. The guidebody 356 may include a guide passage 360 extending along a passage axisPX. The secondary guide 354 may be coupled to the guide body 356 of thetrajectory guide 352 to establish the trajectory T4, which may be alongan aperture axis AA of one or more apertures 364 of the secondary guide354. The secondary guide 354 may be coupled to the guide body 356 suchthat the aperture axis AA is offset from the passage axis PX, asillustrated in FIGS. 25-26 . Relative positioning between the secondaryguide 354 and trajectory guide 352 may provide the surgeon with greaterflexibility in positioning the guide pins GP at trajectories thatclosely approximate the surgical plan 131.

Referring to FIGS. 25-26 , step 274-23 may include positioning thefourth guide pin GP-4 into the bone 376-2 with the trajectory guide 352according to the associated (e.g., fourth) trajectory T4 (see, e.g.,FIGS. 14-15 ) specified by one or more parameters in the surgical plan131. The guide pin GP-4 may be moved in a direction DP4 such that theguide pin GP-4 at least partially received in and through a selected oneof the apertures 364 along the respective aperture axis AA to establishthe fourth trajectory T4. Step 274-23 may occur such that the guide pinsGP-3, GP-4 are substantially parallel to each other subsequent toinserting the guide pins GP-4, GP-4 in the bone 376-2. Placement of theguide pin GP-4 relative to the guide pin GP-3 may be utilized tosubstantially establish alignment to the tibial axis (see, e.g., L2 ofFIG. 3 ) and for subsequent placement of cutting guides.

Referring to FIGS. 28-29 , with continuing reference to FIG. 21 , atstep 274-24 the instrument(s) including the trajectory assembly 350 maybe removed from the surgical site S. One or more cutting guides 378 maybe positioned adjacent to the bone 376-2 relative to the surgical siteS. The cutting guides 378 may be positioned according to thetrajectories T3, T4 of the guide pins GP-3, GP-4. The cutting guides 378can include a first cutting guide 378-1 and a second cutting guide 378-2(FIG. 30 ) including one or more slots dimensioned to receive tooling TTsuch as a saw blade (FIG. 29 ). Step 274-25 may include positioning thefirst cutting guide 378-1 along the pins GP-3, GP-4. The first cuttingguide 378-1 may establish one or more resection planes RP (shown indashed lines in FIG. 28 ). Each resection plane RP may be associatedwith one of the specified reference planes REF of the respective bonemodel 129 (FIG. 4 ). The cutting guide 378-1 can include one or moreapertures distributed at predetermined offsets for positioning the slotsrelative to the bone 376-2. Selection of the particular apertures may bespecified in the surgical plan 131.

At step 274-26, a portion of the bone 376-2 may be resected along theresection plane RP to establish a resection surface 376RS of the bone376-2, as illustrated in FIGS. 29-31 .

Steps 274-24, 274-25 and/or 274-26 may be repeated to resect anadditional portion of the bone 376-2. The second cutting guide 378-2 maybe positioned along the guide pins GP-3, GP-4, as illustrated in FIG. 30, which may occur subsequent to removing the first cutting guide 378-1.The second cutting guide 378-2 may include slots or aperturesdimensioned to receive the respective guide pins GP-3, GP-4. The slotsmay facilitate lateral movement of the second cutting guide 378-2.Another portion of the bone 376-2 may be resected along anotherresection plane RP to establish another resection surface 376RS of thebone 376-2, which may be transverse to the resection surface 376RSestablished with the first cutting guide 378-1, as illustrated in FIG.31 . The transverse cut established by the second resection surface376RS may establish a “gutter cut” of a medial malleolus.

A trajectory assembly 450 may be positioned at the surgical site S.Referring to FIG. 32 , with continuing reference to FIG. 21 , thetrajectory assembly 450 can be the same or can differ from thetrajectory assembly 350. The trajectory assembly 450 includes atrajectory guide 452 and a secondary guide 454 coupled to the trajectoryguide 452 (FIGS. 25-26 ). The joint 375 may be placed in extension tofacilitate positioning of the arm members 458 of the trajectory guide452.

The trajectory guide 452 may be moved into abutment with the first bone476-1 at step 274-22. Step 274-22 may include moving the trajectoryguide 452 in a direction DT1 and into abutment with one of the bones 376to set a trajectory of the guide pin GP-1 relative to tissue includingone of the bones 376 such as the first bone 376-1. Step 274-22 may occursuch that surfaces of the arm members 458 abut predetermined positionsof the bone 376-1 according to the setting(s) and associated surgicalplan 131 (FIG. 2 ), as illustrated in FIGS. 32-34 . The configuredpositions of the arm members 458 relative to the guide body 456 thatestablish the trajectory T1 may be the same or may differ from theconfigured positions of the guide members 358 that establish thetrajectory T3.

Referring to FIGS. 34-35 , with continuing reference to FIG. 21 , step274-23 may include positioning one or more guide members with atrajectory assembly 450, including one or more guide pins GP. Step274-23 may include positioning a first guide pin GP-1 into the bone376-1 with the trajectory guide 452 according to the associated (e.g.,first) trajectory T1 (FIGS. 35-36 ). The guide pin GP-1 may be moved ina direction DP1 such that the guide pin GP-1 is at least partiallyreceived in and through a guide passage 460 of the guide body 456 alongthe passage axis PX to establish the trajectory T1 (FIG. 35 ).

The secondary guide 454 can include one or more apertures 464. Theapertures 464 can be distributed in a row 464-1 about a guide (e.g.,longitudinal) axis GS, as illustrated in FIG. 35 . The secondary guide454 can be configured in the same manner as the secondary guide 354,including setting a relative orientation or position of the trajectoryguide 452 and secondary guide 454 in response to engagement betweenfirst and second interface features 471, 472 at an interface 470.

Step 274-23 may include positioning a second guide pin GP-2 through aselected aperture 464 and then into the bone 376-1 with the secondaryguide 454 according to the associated (e.g., second) trajectory T2 (FIG.35 ). The guide pin GP-2 may be moved in the direction DP2 such that theguide pin GP-2 is at least partially received in and through a selectedone of the apertures 464 along a respective aperture axis AA toestablish the trajectory T2 (FIGS. 35-36 ). Step 274-23 may occur suchthat the guide pins GP-1, GP-2 are substantially parallel to each othersubsequent to inserting the guide pins GP-1, GP-2 in the bone 376-1.

Referring to FIGS. 37-38 , with continuing reference to FIG. 21 , atstep 274-24 the instrument(s), including the trajectory assembly 450,may be removed from the surgical site S. One or more cutting guides 478may be positioned adjacent to the bone 376-1 relative to the surgicalsite S. The cutting guide 478 may be positioned according to thetrajectories T1, T1 of the guide pins GP-1, GP-2 (FIG. 37 ). The cuttingguide 478 can include one or more slots dimensioned to receive toolingTT such as a saw (FIG. 38 ). Step 274-25 may include positioning thecutting guide 478 along the guide pins GP-1, GP-2. The cutting guide 478may establish one or more resection planes RP (shown in dashed lines inFIG. 38 ). Each resection plane RP may be associated with one of thereference planes REF of the respective bone model 129 (FIG. 4 ). At step274-26, a portion of the bone 376-1 may be resected along the resectionplane RP to establish a resection surface 376RS of the bone 376-1, asillustrated in FIG. 38 .

Step 274-26 may include forming one or more relief cuts in the firstbone 376-1 and/or second bone 376-2. The relief cuts may be formed to atleast partially or substantially remove the overlapping volumesdetermined at step 274-16 and associated modified bone models 129-1″and/or 129-2″ established at step 274-17.

Referring to FIGS. 39-40 , with continuing reference to FIG. 21 , thecutting guide 478 can be removed from the surgical site S. At step274-27, the resection surfaces 376RS of the first and second bones376-1, 376-2 may be moved into abutment. Step 274-27 may includepositioning the bones 376-1, 376-2 to establish a contact area thatsubstantially corresponds to the contact region CR of the associatedsurgical plan 131 (see, e.g., FIGS. 2 and 6 ). Step 274-27 may includepositioning the bones 376-1, 376-2 to establish cortical-to-corticalcontact along the resection surfaces 376RS that substantiallycorresponds to the localized support regions LSR of the associatedsurgical plan 131 (see, e.g., FIGS. 6 and 9-10 ). The surgeon may adjustthe relative position between the resection surfaces 376RS of the bones376-1, 376-2.

At step 274-28, one or more implants 380 may be positioned relative tothe bones 376-1, 376-2. The implant 380 may be associated with animplant model 130 of the surgical plan 131 (see, e.g., FIGS. 2 and 12-13). Step 274-28 may occur subsequent to moving the resection surfaces376RS of the bones 376-1, 376-2 into abutment. The implant 380 may bepositioned to span across an interface between the bones 376-1, 376-2.

At step 274-29, the implant(s) 380 may be secured to the bones 376-1,376-2. Various techniques may be utilized to secure the implant 380,including one or more fasteners F (FIG. 40 ). Exemplary fasteners caninclude nails, pins, locking and/or non-locking compression screws,suture, etc. At step 274-30, one or more finishing operations may beperformed. Exemplary finishing operations may include closing anincision at the surgical site S.

The novel devices and methods of this disclosure provide versatility indimensioning or shaping resection surfaces at a surgical site. Thedisclosed planning systems and methods may be utilized to determineresection characteristics and sufficiency of contact surfaces to promotebone fusion and stability. The surgeon or assistant may interact withthe disclosed planning systems to set and adjust the resectioncharacteristics, including adjusting resection planes associated withthe selected bone models. The disclosed planning systems and methods maypresent the surgeon or assistant with parameters associated with theselected resection planes and other characteristics, includingparameters associated with a contact area between the adjacent resectionsurfaces, cortical and cancellous coverage, and shortening of therespective bones, which may be utilized to establish relatively greatercontact areas and improve bone fusion and healing at the surgical site.The disclosed trajectory assemblies, including the disclosed trajectoryguides and secondary guides, may precisely establish trajectories ofguide members inserted into bone, which can be utilized to moreaccurately form resection surfaces according to a preoperative planestablished for the patient.

The disclosed systems and methods can facilitate implant and screwpositioning, osteotomy position on adjacent bones including a tibia andtalus in a manner that improves surface coverage. The disclosedtrajectory assemblies and cutting guides may be reusable and may beconfigured according to settings established in a surgical plan. Thedisclosed systems and methods can be utilized to reduce operative timeand complexity.

Although the different non-limiting embodiments are illustrated ashaving specific components or steps, the embodiments of this disclosureare not limited to those particular combinations. It is possible to usesome of the components or features from any of the non-limitingembodiments in combination with features or components from any of theother non-limiting embodiments.

It should be understood that like reference numerals identifycorresponding or similar elements throughout the several drawings. Itshould further be understood that although a particular componentarrangement is disclosed and illustrated in these exemplary embodiments,other arrangements could also benefit from the teachings of thisdisclosure.

The foregoing description shall be interpreted as illustrative and notin any limiting sense. A worker of ordinary skill in the art wouldunderstand that certain modifications could come within the scope ofthis disclosure. For these reasons, the following claims should bestudied to determine the true scope and content of this disclosure.

What is claimed is:
 1. An assembly for preparation of a surgical sitecomprising: a trajectory guide including a guide body and at least onearm member coupled to the guide body, the guide body including a guidepassage extending along a passage axis, and the at least one arm membermoveable relative to the guide body to set a trajectory of a first guidepin insertable through the guide passage relative to bone; and asecondary guide including a main body having at least one aperture, theat least one aperture dimensioned to at least partially receive a secondguide pin along an aperture axis, and the secondary guide coupled to theguide body such that the aperture axis is offset from the passage axis.2. The assembly as recited in claim 1, wherein the aperture axis issubstantially parallel to the passage axis.
 3. The assembly as recitedin claim 1, wherein the main body extends along a guide axis, and the atleast one aperture includes a first row of apertures distributed aboutthe guide axis.
 4. The assembly as recited in claim 3, wherein the atleast one aperture includes a second row of apertures distributed aboutthe guide axis, the second row of apertures being outward of the firstrow of apertures relative to the guide axis.
 5. The assembly as recitedin claim 4, wherein each aperture of the first row of apertures issubstantially circumferentially aligned with a respective aperture ofthe second row of apertures relative to the guide axis.
 6. The assemblyas recited in claim 1, wherein the main body includes a sleeve portionand a flange portion extending outwardly from a perimeter of the sleeveportion, the at least one aperture is established along the flangeportion, and the sleeve portion has a sleeve passage dimensioned to atleast partially receive a proximal end portion of the guide body.
 7. Theassembly as recited in claim 6, wherein the trajectory guide includes anabutment along an outer periphery of the guide body, and the secondaryguide is translatable along the passage axis to engage the abutment suchthat relative movement between the secondary guide and guide body islimited relative to the pass age axis.
 8. The assembly as recited inclaim 7, wherein the trajectory guide includes a first interface featurealong the guide body, the secondary guide includes a second interfacefeature along the sleeve portion, and the first interface feature isdimensioned to engage with the second interface feature to limitrelative rotation between the guide body and the secondary guide.
 9. Theassembly as recited in claim 8, wherein the first interface feature is aprotrusion extending outwardly from the outer periphery of the guidebody, and the second interface feature includes at least one groovealong the sleeve passage of the sleeve portion, and the protrusion isinsertable in the at least one groove to limit relative rotation betweenthe guide body and the secondary guide.
 10. The assembly as recited inclaim 9, wherein the at least one groove includes an array of groovesdistributed along the sleeve passage of the sleeve portion, and theprotrusion is insertable within a selected one of the grooves to set acircumferential position of the at least one aperture relative to thepassage axis.
 11. The assembly as recited in claim 7, wherein theabutment is an annular flange extending outwardly from the guide body.12. The assembly as recited in claim 6, wherein the main body extendsalong a guide axis, and the at least one aperture includes a first rowof apertures distributed about the guide axis.
 13. The assembly asrecited in claim 12, wherein the at least one aperture includes a secondrow of apertures distributed about the guide axis, the second row ofapertures being outward of the first row of apertures relative to theguide axis.
 14. The assembly as recited in claim 13, wherein eachaperture of the first row of apertures is substantiallycircumferentially aligned with a respective aperture of the second rowof apertures relative to the guide axis.
 14. The assembly as recited inclaim 13, wherein the flange portion includes a first section and asecond section that establish a stepped arrangement, the first row ofapertures is established along the first section, and the second row ofapertures is established along the second section.
 15. The assembly asrecited in claim 13, wherein the secondary guide is releasably securedto the trajectory guide.
 16. The assembly as recited in claim 14,wherein: the secondary guide is moveable about the guide axis; thetrajectory guide includes a first interface feature along the guidebody, the secondary guide includes a second interface feature along thesleeve portion, and the first and second interface features cooperate toestablish a plurality of discrete positions relative to the guide axis;and the first interface feature is dimensioned to engage with the secondinterface feature to set a circumferential position of the at least oneaperture relative to the passage axis.
 17. The assembly as recited inclaim 1, wherein the secondary guide is dimensioned such that aprojection of the aperture axis is offset from the trajectory guide. 18.The assembly as recited in claim 1, wherein the at least one arm memberincludes a plurality of arm members independently moveable relative tothe guide body to set the trajectory.
 19. The assembly as recited inclaim 1, wherein the secondary guide is integrally formed with thetrajectory guide.
 20. The assembly as recited in claim 1, wherein thesecondary guide is releasably secured to the trajectory guide.